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Sample records for forms motile inclusions

  1. The Cauliflower Mosaic Virus Protein P6 Forms Motile Inclusions That Traffic along Actin Microfilaments and Stabilize Microtubules1[W][OA

    PubMed Central

    Harries, Phillip A.; Palanichelvam, Karuppaiah; Yu, Weichang; Schoelz, James E.; Nelson, Richard S.

    2009-01-01

    The gene VI product (P6) of Cauliflower mosaic virus (CaMV) is a multifunctional protein known to be a major component of cytoplasmic inclusion bodies formed during CaMV infection. Although these inclusions are known to contain virions and are thought to be sites of translation from the CaMV 35S polycistronic RNA intermediate, the precise role of these bodies in the CaMV infection cycle remains unclear. Here, we examine the functionality and intracellular location of a fusion between P6 and GFP (P6-GFP). We initially show that the ability of P6-GFP to transactivate translation is comparable to unmodified P6. Consequently, our work has direct application for the large body of literature in which P6 has been expressed ectopically and its functions characterized. We subsequently found that P6-GFP forms highly motile cytoplasmic inclusion bodies and revealed through fluorescence colocalization studies that these P6-GFP bodies associate with the actin/endoplasmic reticulum network as well as microtubules. We demonstrate that while P6-GFP inclusions traffic along microfilaments, those associated with microtubules appear stationary. Additionally, inhibitor studies reveal that the intracellular movement of P6-GFP inclusions is sensitive to the actin inhibitor, latrunculin B, which also inhibits the formation of local lesions by CaMV in Nicotiana edwardsonii leaves. The motility of P6 along microfilaments represents an entirely new property for this protein, and these results imply a role for P6 in intracellular and cell-to-cell movement of CaMV. PMID:19028879

  2. Cyclodextrin Inclusion Polymers Forming Hydrogels

    NASA Astrophysics Data System (ADS)

    Li, Jun

    This chapter reviews the advances in the developments of supramolecular hydrogels based on the polypseudorotaxanes and polyrotaxanes formed by inclusion complexes of cyclodextrins threading onto polymer chains. Both physical and chemical supramolecular hydrogels of many different types are discussed with respect to their preparation, structure, property, and gelation mechanism. A large number of physical supramolecular hydrogels were formed induced by self-assembly of densely packed cyclodextrin rings threaded on polymer or copolymer chains acting as physical crosslinking points. The thermo-reversible and thixotropic properties of these physical supramolecular hydrogels have inspired their applications as injectable drug delivery systems. Chemical supramolecular hydrogels synthesized from polypseudorotaxanes and polyrotaxanes were based on the chemical crosslinking of either the cyclodextrin molecules or the included polymer chains. The chemical supramolecular hydrogels were often made biodegradable through incorporation of hydrolyzable threading polymers, end caps, or crosslinkers, for their potential applications as biomaterials.

  3. Staphylococcus aureus forms spreading dendrites that have characteristics of active motility

    PubMed Central

    Pollitt, Eric J. G.; Crusz, Shanika A.; Diggle, Stephen P.

    2015-01-01

    Staphylococcus aureus is historically regarded as a non-motile organism. More recently it has been shown that S. aureus can passively move across agar surfaces in a process called spreading. We re-analysed spreading motility using a modified assay and focused on observing the formation of dendrites: branching structures that emerge from the central colony. We discovered that S. aureus can spread across the surface of media in structures that we term ‘comets’, which advance outwards and precede the formation of dendrites. We observed comets in a diverse selection of S. aureus isolates and they exhibit the following behaviours: (1) They consist of phenotypically distinct cores of cells that move forward and seed other S. aureus cells behind them forming a comet ‘tail’; (2) they move when other cells in the comet tail have stopped moving; (3) the comet core is held together by a matrix of slime; and (4) the comets etch trails in the agar as they move forwards. Comets are not consistent with spreading motility or other forms of passive motility. Comet behaviour does share many similarities with a form of active motility known as gliding. Our observations therefore suggest that S. aureus is actively motile under certain conditions. PMID:26680153

  4. Complex patterns formed by motile cells of Escherichia coli

    NASA Astrophysics Data System (ADS)

    Budrene, Elena O.; Berg, Howard C.

    1991-02-01

    WHEN chemotactic strains of the bacterium Escherichia coli are inoculated on semi-solid agar containing mixtures of amino acids or sugars, the cells swarm outwards in a series of concentric rings: they respond to spatial gradients of attractants generated by uptake and catabolism1-3. Cells also drift up gradients generated artificially, for example by diffusion from the tip of a capillary tube4 or by mixing5. Here we describe conditions under which cells aggregate in response to gradients of attractant which they excrete themselves. When cells are grown in semi-solid agar on intermediates of the tricarboxylic acid cycle, they form symmetrical arrays of spots or stripes that arise sequentially. When cells in a thin layer of liquid culture are exposed to these compounds, spots appear synchronously, more randomly arrayed. In either case, the patterns are stationary. The attractant is a chemical sensed by the aspartate receptor. Its excretion can be triggered by oxidative stress. As oxygen is limiting at high cell densities, aggregation might serve as a mechanism for collective defence.

  5. [Inclusion Bodies are Formed in SFTSV-infected Human Macrophages].

    PubMed

    Jin, Cong; Song, Jingdong; Han, Ying; Li, Chuan; Qiu, Peihong; Liang, Mifang

    2016-01-01

    The severe fever with thrombocytopenia syndrome virus (SFTSV) is a new member in the genus Phlebovirus of the family Bunyaviridae identified in China. The SFTSV is also the causative pathogen of an emerging infectious disease: severe fever with thrombocytopenia syndrome. Using immunofluorescent staining and confocal microscopy, the intracellular distribution of nucleocapsid protein (NP) in SFTSV-infected THP-1 cells was investigated with serial doses of SFTSV at different times after infection. Transmission electron microscopy was used to observe the ultrafine intracellular structure of SFTSV-infected THP-1 cells at different times after infection. SFTSV NP could form intracellular inclusion bodies in infected THP-1 cells. The association between NP-formed inclusion bodies and virus production was analyzed: the size of the inclusion body formed 3 days after infection was correlated with the viral load in supernatants collected 7 days after infection. These findings suggest that the inclusion bodies formed in SFTSV-infected THP-1 cells could be where the SFTSV uses host-cell proteins and intracellular organelles to produce new viral particles.

  6. A tunable sequential and periodic pattern formed by coupling cell motility with density

    NASA Astrophysics Data System (ADS)

    Huang, Jiandong

    2011-03-01

    The ability of living organisms to form patterns is an untapped resource for synthetic biology. We aim to generate unique patterns by rewiring the genetic circuitry controlling cell motility. Specifically, E. coli cells are programmed to regulate their movement by sensing local cell density. Interesting patterns are formed by newly engineered cells. An engineered low-density mover strain spreads outwards and autonomously forms a sequential and periodic pattern. Moreover, we build a theoretical model that satisfactorily fits our current experimental data, and also predicts some parameters which may significantly affect the pattern formation. The study of this self-organized spatial distribution of cells may help us to probe the principles underlying the formation of natural biological patterns, and to prepare for future engineering of biological structures.

  7. Structure-function analysis of dynein light chain 1 identifies viable motility mutants in bloodstream-form Trypanosoma brucei.

    PubMed

    Ralston, Katherine S; Kisalu, Neville K; Hill, Kent L

    2011-07-01

    The flagellum of Trypanosoma brucei is an essential and multifunctional organelle that is receiving increasing attention as a potential drug target and as a system for studying flagellum biology. RNA interference (RNAi) knockdown is widely used to test the requirement for a protein in flagellar motility and has suggested that normal flagellar motility is essential for viability in bloodstream-form trypanosomes. However, RNAi knockdown alone provides limited functional information because the consequence is often loss of a multiprotein complex. We therefore developed an inducible system that allows functional analysis of point mutations in flagellar proteins in T. brucei. Using this system, we identified point mutations in the outer dynein light chain 1 (LC1) that allow stable assembly of outer dynein motors but do not support propulsive motility. In procyclic-form trypanosomes, the phenotype of LC1 mutants with point mutations differs from the motility and structural defects of LC1 knockdowns, which lack the outer-arm dynein motor. Thus, our results distinguish LC1-specific functions from broader functions of outer-arm dynein. In bloodstream-form trypanosomes, LC1 knockdown blocks cell division and is lethal. In contrast, LC1 point mutations cause severe motility defects without affecting viability, indicating that the lethal phenotype of LC1 RNAi knockdown is not due to defective motility. Our results demonstrate for the first time that normal motility is not essential in bloodstream-form T. brucei and that the presumed connection between motility and viability is more complex than might be interpreted from knockdown studies alone. These findings open new avenues for dissecting mechanisms of flagellar protein function and provide an important step in efforts to exploit the potential of the flagellum as a therapeutic target in African sleeping sickness.

  8. Yeast prions form infectious amyloid inclusion bodies in bacteria

    PubMed Central

    2012-01-01

    Background Prions were first identified as infectious proteins associated with fatal brain diseases in mammals. However, fungal prions behave as epigenetic regulators that can alter a range of cellular processes. These proteins propagate as self-perpetuating amyloid aggregates being an example of structural inheritance. The best-characterized examples are the Sup35 and Ure2 yeast proteins, corresponding to [PSI+] and [URE3] phenotypes, respectively. Results Here we show that both the prion domain of Sup35 (Sup35-NM) and the Ure2 protein (Ure2p) form inclusion bodies (IBs) displaying amyloid-like properties when expressed in bacteria. These intracellular aggregates template the conformational change and promote the aggregation of homologous, but not heterologous, soluble prionogenic molecules. Moreover, in the case of Sup35-NM, purified IBs are able to induce different [PSI+] phenotypes in yeast, indicating that at least a fraction of the protein embedded in these deposits adopts an infectious prion fold. Conclusions An important feature of prion inheritance is the existence of strains, which are phenotypic variants encoded by different conformations of the same polypeptide. We show here that the proportion of infected yeast cells displaying strong and weak [PSI+] phenotypes depends on the conditions under which the prionogenic aggregates are formed in E. coli, suggesting that bacterial systems might become useful tools to generate prion strain diversity. PMID:22731490

  9. Forms of Leadership that Promote Inclusive Education in Cypriot Schools

    ERIC Educational Resources Information Center

    Angelides, Panayiotis

    2012-01-01

    A primary goal of many educational systems in different countries of the world is the offering of equal opportunities in education. My engagement with the literature that relates to inclusive education as well as the literature that relates to educational leadership leads to the conclusion that if we are interested in moving towards more inclusive…

  10. Zr inclusions in actinide–Zr alloys: New data and ideas about how they form

    SciTech Connect

    Janney, Dawn E.; O’Holleran, Thomas P.

    2015-05-01

    High-Zr inclusions are common in actinide–Zr alloys despite phase diagrams indicating that these alloys should not contain a high-Zr phase. The inclusions may contain enough Zr to cause significant differences between bulk compositions and those of inclusion-free areas, leading to possible errors in interpreting data if the inclusions are not considered. This paper presents data from high-Zr inclusions in a complex U–Np–Pu–Am–Zr–RE alloy. It is suggested that the high-Zr inclusions nucleated as high-Zr solid solutions at interfaces with high-actinide RE liquids, then unmixed to form nanometer-scale high-actinide sub-inclusions.

  11. Anthocyanin Vacuolar Inclusions Form by a Microautophagy Mechanism

    PubMed Central

    Chanoca, Alexandra; Ueda, Takashi; Grotewold, Erich

    2015-01-01

    Anthocyanins are flavonoid pigments synthesized in the cytoplasm and stored inside vacuoles. Many plant species accumulate densely packed, 3- to 10-μm diameter anthocyanin deposits called anthocyanin vacuolar inclusions (AVIs). Despite their conspicuousness and importance in organ coloration, the origin and nature of AVIs have remained controversial for decades. We analyzed AVI formation in cotyledons of different Arabidopsis thaliana genotypes grown under anthocyanin inductive conditions and in purple petals of lisianthus (Eustoma grandiorum). We found that cytoplasmic anthocyanin aggregates in close contact with the vacuolar surface are directly engulfed by the vacuolar membrane in a process reminiscent of microautophagy. The engulfed anthocyanin aggregates are surrounded by a single membrane derived from the tonoplast and eventually become free in the vacuolar lumen like an autophagic body. Neither endosomal/prevacuolar trafficking nor the autophagy ATG5 protein is involved in the formation of AVIs. In Arabidopsis, formation of AVIs is promoted by both an increase in cyanidin 3-O-glucoside derivatives and by depletion of the glutathione S-transferase TT19. We hypothesize that this novel microautophagy mechanism also mediates the transport of other flavonoid aggregates into the vacuole. PMID:26342015

  12. Inclusion.

    ERIC Educational Resources Information Center

    Nathanson, Jeanne H., Ed.

    1992-01-01

    This theme journal issue focuses on current activities of the Office of Special Education and Rehabilitative Services which stress inclusion of students with disabilities in the mainstream. It begins with a message from the Assistant Secretary, Robert R. Davila which examines the full meaning of an "inclusive" education. Next, Barbara…

  13. AglZ Is a Filament-Forming Coiled-Coil Protein Required for Adventurous Gliding Motility of Myxococcus xanthus

    PubMed Central

    Yang, Ruifeng; Bartle, Sarah; Otto, Rebecca; Stassinopoulos, Angela; Rogers, Matthew; Plamann, Lynda; Hartzell, Patricia

    2004-01-01

    The aglZ gene of Myxococcus xanthus was identified from a yeast two-hybrid assay in which MglA was used as bait. MglA is a 22-kDa cytoplasmic GTPase required for both adventurous and social gliding motility and sporulation. Genetic studies showed that aglZ is part of the A motility system, because disruption or deletion of aglZ abolished movement of isolated cells and aglZ sglK double mutants were nonmotile. The aglZ gene encodes a 153-kDa protein that interacts with purified MglA in vitro. The N terminus of AglZ shows similarity to the receiver domain of two-component response regulator proteins, while the C terminus contains heptad repeats characteristic of coiled-coil proteins, such as myosin. Consistent with this motif, expression of AglZ in Escherichia coli resulted in production of striated lattice structures. Similar to the myosin heavy chain, the purified C-terminal coiled-coil domain of AglZ forms filament structures in vitro. PMID:15342587

  14. AglZ is a filament-forming coiled-coil protein required for adventurous gliding motility of Myxococcus xanthus.

    PubMed

    Yang, Ruifeng; Bartle, Sarah; Otto, Rebecca; Stassinopoulos, Angela; Rogers, Matthew; Plamann, Lynda; Hartzell, Patricia

    2004-09-01

    The aglZ gene of Myxococcus xanthus was identified from a yeast two-hybrid assay in which MglA was used as bait. MglA is a 22-kDa cytoplasmic GTPase required for both adventurous and social gliding motility and sporulation. Genetic studies showed that aglZ is part of the A motility system, because disruption or deletion of aglZ abolished movement of isolated cells and aglZ sglK double mutants were nonmotile. The aglZ gene encodes a 153-kDa protein that interacts with purified MglA in vitro. The N terminus of AglZ shows similarity to the receiver domain of two-component response regulator proteins, while the C terminus contains heptad repeats characteristic of coiled-coil proteins, such as myosin. Consistent with this motif, expression of AglZ in Escherichia coli resulted in production of striated lattice structures. Similar to the myosin heavy chain, the purified C-terminal coiled-coil domain of AglZ forms filament structures in vitro.

  15. The surface layer protein of Bacillus thuringiensis CTC forms unique intracellular parasporal inclusion body.

    PubMed

    Zhu, Chenguang; Yu, Ziniu

    2008-08-01

    Bacillus thuringiensis subsp. finitimus strain CTC forms round parasporal inclusion body. The inclusion body protein gene ctc has been cloned and characterized. Sequence homology analysis reveals that the amino acid sequence of CTC protein shows 87% identity with the surface layer (S-layer) protein Sap (GenBank Z36946) in B. anthracis. In this report, transmission electron microscope observation showed that CTC formed intracellular parasporal inclusion body and sheet structure of S-layer-like protein at the spore phase. Furthermore, the ctc gene was transformed into an acrystalliferous B. thuringiensis strain BMB171. The resulting transformant could form parasporal body which had the same shape and molecular weight of protein with that of B. thuringiensis CTC. These results, together with the sequence homology analysis of ctc gene, confirmed that the unique intracellular parasporal inclusion body of B. thuringiensis was comprised of S-layer protein.

  16. Complex Nonmetallic Inclusions Formed in Billets Heated for Rolling and Characteristics of Structural Steels

    NASA Astrophysics Data System (ADS)

    Zaitsev, A. I.; Koldaev, A. V.; Arutyunyan, N. A.; Shaposhnikov, N. G.; Dunaev, S. F.

    2017-03-01

    Complex bimetallic inclusions formed in billets from steels 09G2S and K52 during heating for rolling are studied by methods of electron microscopy and local x-ray spectrum analysis. To check the established evolution of oxide inclusions based on aluminomagnesium spinel and other oxide compositions, individual inclusions of manganese sulfide and complex oxide-sulfide inclusions, a method developed by the Severstal'Company and the Karpov NIFKhI for determining the content of corrosion-active nonmetallic inclusions (CANI) as a function of the heating mode is applied to the steels studied. It is recommended to increase the temperature and duration of heating of billets for hot rolling in order to lower the content of CANI and to raise the resistance of the steels to local corrosion.

  17. Supramolecular aggregates formed by sulfadiazine and sulfisomidine inclusion complexes with α- and β-cyclodextrins.

    PubMed

    Rajendiran, N; Venkatesh, G; Saravanan, J

    2014-08-14

    Sulfadiazine (SDA) and sulfisomidine (SFM) inclusion complexes with two cyclodextrins (α-CD and β-CD) are studied in aqueous as well as in solid state. The inclusion complexes are characterized by UV-visible, fluorescence, time correlated single photon counting, FTIR, DSC, PXRD and (1)H NMR techniques. The self assembled SDA/CD and SFM/CD inclusion complexes form different types of nano and microstructures. The self assembled nanoparticle morphologies are studied using SEM and TEM techniques. SDA/α-CD complex is formed hierarchal morphology, SDA/β-CD and SFM/β-CD complexes form the nanosheet self assembly. However, SFM/α-CD complex forms nanoporous sheet self assembly. van der Waals, hydrophobic and hydrogen bonding interaction play a vital role in the self assembling process.

  18. The N-DRC forms a conserved biochemical complex that maintains outer doublet alignment and limits microtubule sliding in motile axonemes

    PubMed Central

    Bower, Raqual; Tritschler, Douglas; VanderWaal, Kristyn; Perrone, Catherine A.; Mueller, Joshua; Fox, Laura; Sale, Winfield S.; Porter, M. E.

    2013-01-01

    The nexin–dynein regulatory complex (N-DRC) is proposed to coordinate dynein arm activity and interconnect doublet microtubules. Here we identify a conserved region in DRC4 critical for assembly of the N-DRC into the axoneme. At least 10 subunits associate with DRC4 to form a discrete complex distinct from other axonemal substructures. Transformation of drc4 mutants with epitope-tagged DRC4 rescues the motility defects and restores assembly of missing DRC subunits and associated inner-arm dyneins. Four new DRC subunits contain calcium-signaling motifs and/or AAA domains and are nearly ubiquitous in species with motile cilia. However, drc mutants are motile and maintain the 9 + 2 organization of the axoneme. To evaluate the function of the N-DRC, we analyzed ATP-induced reactivation of isolated axonemes. Rather than the reactivated bending observed with wild-type axonemes, ATP addition to drc-mutant axonemes resulted in splaying of doublets in the distal region, followed by oscillatory bending between pairs of doublets. Thus the N-DRC provides some but not all of the resistance to microtubule sliding and helps to maintain optimal alignment of doublets for productive flagellar motility. These findings provide new insights into the mechanisms that regulate motility and further highlight the importance of the proximal region of the axoneme in generating flagellar bending. PMID:23427265

  19. Architecture of Amylose Supramolecules in Form of Inclusion Complexes by Phosphorylase-Catalyzed Enzymatic Polymerization

    PubMed Central

    Kadokawa, Jun-ichi

    2013-01-01

    This paper reviews the architecture of amylose supramolecules in form of inclusion complexes with synthetic polymers by phosphorylase-catalyzed enzymatic polymerization. Amylose is known to be synthesized by enzymatic polymerization using α-d-glucose 1-phosphate as a monomer, by phosphorylase catalysis. When the phosphorylase-catalyzed enzymatic polymerization was conducted in the presence of various hydrophobic polymers, such as polyethers, polyesters, poly(ester-ether), and polycarbonates as a guest polymer, such inclusion supramolecules were formed by the hydrophobic interaction in the progress of polymerization. Because the representation of propagation in the polymerization is similar to the way that a vine of a plant grows, twining around a rod, this polymerization method for the formation of amylose-polymer inclusion complexes was proposed to be named “vine-twining polymerization”. To yield an inclusion complex from a strongly hydrophobic polyester, the parallel enzymatic polymerization system was extensively developed. The author found that amylose selectively included one side of the guest polymer from a mixture of two resemblant guest polymers, as well as a specific range in molecular weights of the guest polymers poly(tetrahydrofuran) (PTHF) in the vine-twining polymerization. Selective inclusion behavior of amylose toward stereoisomers of chiral polyesters, poly(lactide)s, also appeared in the vine-twining polymerization. PMID:24970172

  20. Seeking sunlight: rapid phototactic motility of filamentous mat-forming cyanobacteria optimize photosynthesis and enhance carbon burial in Lake Huron’s submerged sinkholes

    PubMed Central

    Biddanda, Bopaiah A.; McMillan, Adam C.; Long, Stephen A.; Snider, Michael J.; Weinke, Anthony D.

    2015-01-01

    We studied the motility of filamentous mat-forming cyanobacteria consisting primarily of Oscillatoria-like cells growing under low-light, low-oxygen, and high-sulfur conditions in Lake Huron’s submerged sinkholes using in situ observations, in vitro measurements and time-lapse microscopy. Gliding movement of the cyanobacterial trichomes (100–10,000 μm long filaments, composed of cells ∼10 μm wide and ∼3 μm tall) revealed individual as well as group-coordinated motility. When placed in a petri dish and dispersed in ground water from the sinkhole, filaments re-aggregated into defined colonies within minutes, then dispersed again. Speed of individual filaments increased with temperature from ∼50 μm min-1 or ∼15 body lengths min-1 at 10°C to ∼215 μm min-1 or ∼70 body lengths min-1 at 35°C – rates that are rapid relative to non-flagellated/ciliated microbes. Filaments exhibited precise and coordinated positive phototaxis toward pinpoints of light and congregated under the light of foil cutouts. Such light-responsive clusters showed an increase in photosynthetic yield – suggesting phototactic motility aids in light acquisition as well as photosynthesis. Once light source was removed, filaments slowly spread out evenly and re-aggregated, demonstrating coordinated movement through inter-filament communication regardless of light. Pebbles and pieces of broken shells placed upon intact mat were quickly covered by vertically motile filaments within hours and became fully buried in the anoxic sediments over 3–4 diurnal cycles – likely facilitating the preservation of falling debris. Coordinated horizontal and vertical filament motility optimize mat cohesion and dynamics, photosynthetic efficiency and sedimentary carbon burial in modern-day sinkhole habitats that resemble the shallow seas in Earth’s early history. Analogous cyanobacterial motility may have played a key role in the oxygenation of the planet by optimizing photosynthesis while

  1. Characterization of intracellular inclusions formed by Pseudomonas oleovorans during growth on octane.

    PubMed Central

    de Smet, M J; Eggink, G; Witholt, B; Kingma, J; Wynberg, H

    1983-01-01

    The growth of Pseudomonas oleovorans on n-octane was characterized by the formation of intracellular structures. These inclusions were isolated and characterized. Morphologically, they resembled the poly-beta-hydroxybutyrate granules found in Bacillus cereus, as shown by freeze-fracture electron microscopy. The elemental analysis of isolated granules showed, however, that they do not contain poly-beta-hydroxybutyric acid. Instead, the analysis was consistent with a C8 polyester, which interpretation was supported by the fatty acid analysis of hydrolyzed granules. From the evidence presented here, we conclude that P. oleovorans forms poly-beta-hydroxyoctanoate granules when grown on n-octane. Images PMID:6841319

  2. Characterization of inclusion bodies with cytoprotective properties formed by seipinopathy-linked mutant seipin.

    PubMed

    Ito, Daisuke; Yagi, Takuya; Ikawa, Masahito; Suzuki, Norihiro

    2012-02-01

    Gain-of-toxic mutations in the N-glycosylation motif of the seipin/BSCL2 gene (namely, the N88S and S90L mutations) cause autosomal dominant motor neuron diseases, termed 'seipinopathy'. Expressed mutant seipin is improperly folded and accumulates in the endoplasmic reticulum (ER), leading to an unfolded protein response (UPR). Furthermore, cells expressing mutant seipin contain unique cytoplasmic inclusion bodies (IB) that form via a different mechanism from that of ubiquitinated inclusions, or aggresomes. Whether the formation of these IB is pathogenic or protective in neurodegenerative diseases remains unclear. Here, we determined that mutant seipin IB are negative for two well-established ER markers, immunoglobulin-heavy-chain-binding protein and calnexin, indicating a distinct compartmentalization from the main ER, and that mutant seipin IB are formed via a mechanism that is independent of major UPR transducers and ER chaperons. Electron microscopy and coexpression study with variant α1-antitrypsin cDNA showed that seipin IB are compatible with unique cytoplasmic vesicles known as ER-derived protective organelles (ERPO). We also obtained evidence that seipin IB exhibit a cytoprotective property via the attenuation of ER stress. These findings suggest that ERPO, such as seipin IB, are a novel adaptation machinery against the accumulation of unfolded proteins in the ER.

  3. A novel automated method for enumeration of Chlamydia trachomatis inclusion forming units.

    PubMed

    Wang, Su; Indrawati, Lani; Wooters, Melissa; Caro-Aguilar, Ivette; Field, Jodie; Kaufhold, Robin; Payne, Angela; Caulfield, Michael J; Smith, Jeffrey G; Heinrichs, Jon H

    2007-07-31

    Chlamydia trachomatis is an obligate intracellular pathogen that primarily infects epithelial cells. Traditional methods for quantification of inclusion forming units (IFUs) rely upon infection of epithelial cell monolayers in vitro. Following incubation for approximately 2 days, inclusion bodies that result from infection of cells are detected by immunofluorescent staining with an antibody conjugated to a fluorescent dye. These inclusion bodies are then manually counted by microscopic examination of multiple, randomly selected fields of view. This requires substantial operator time and is subject to investigator bias. We have developed a novel method in which we utilize an automated microplate ImmunoSpot reader to count C. trachomatis IFUs. Following infection of epithelial cells in a 96-well plate and subsequent incubation, IFUs are fixed and detected with an anti-C. trachomatis LPS monoclonal antibody. Immobilized antibody is detected with a biotinylated secondary antibody and visualized enzymatically with streptavidin-alkaline phosphatase and the colorimetric substrate nitro-blue tetrazolium chloride/5-bromo-4-chloro-3-indolyl-phospate (NBT/BCIP). IFUs are then enumerated with the ImmunoSpot system. This method has been used to quantify IFUs from all cell lines traditionally used for chlamydial propagation, including L929, McCoy, HeLa and HaK cells. IFU numbers obtained are comparable to those determined by traditional microscopic counting. In addition, the method can be applied to rapid determination of serum-neutralizing titers for vaccine studies, and we have also applied this approach to quantify Chlamydia recovered from vaginal swabs collected from infected animals. This method provides for rapid enumeration of IFU counts while minimizing investigator bias and has potential applications for both research and diagnostic use.

  4. Hot-melt extrusion as a continuous manufacturing process to form ternary cyclodextrin inclusion complexes.

    PubMed

    Thiry, Justine; Krier, Fabrice; Ratwatte, Shenelka; Thomassin, Jean-Michel; Jerome, Christine; Evrard, Brigitte

    2017-01-01

    The aim of this study was to evaluate hot-melt extrusion (HME) as a continuous process to form cyclodextrin (CD) inclusion complexes in order to increase the solubility and dissolution rate of itraconazole (ITZ), a class II model drug molecule of the Biopharmaceutics Classification System. Different CD derivatives were tested in a 1:1 (CD:ITZ) molar ratio to obtain CD ternary inclusion complexes in the presence of a polymer, namely Soluplus(®) (SOL). The CD used in this series of experiments were β-cyclodextrin (βCD), hydroxypropyl-β-cyclodextrin (HPβCD) with degrees of substitution of 0.63 and 0.87, randomly methylated β-cyclodextrin (Rameb(®)), sulfobutylether-β-cyclodextrin (Captisol(®)) and methyl-β-cyclodextrin (Crysmeb(®)). Rheology testing and mini extrusion using a conical twin screw mini extruder were performed to test the processability of the different CD mixtures since CD are not thermoplastic. This allowed Captisol(®) and Crysmeb(®) to be discarded from the study due to their high impact on the viscosity of the SOL/ITZ mixture. The remaining CD were processed by HME in an 18mm twin screw extruder. Saturation concentration measurements confirmed the enhancement of solubility of ITZ for the four CD formulations. Biphasic dissolution tests indicated that all four formulations had faster release profiles compared to the SOL/ITZ solid dispersion. Formulations of HPβCD 0.63 and Rameb(®) even reached 95% of ITZ released in both phases after 1h. The formulations were characterized using thermal differential scanning calorimetry and attenuated total reflectance infra-red analysis. These analyses confirmed that the increased release profile was due to the formation of ternary inclusion complexes.

  5. Transport, motility, biofilm forming potential and survival of Bacillus subtilis exposed to cold temperature and freeze-thaw.

    PubMed

    Asadishad, Bahareh; Olsson, Adam L J; Dusane, Devendra H; Ghoshal, Subhasis; Tufenkji, Nathalie

    2014-07-01

    In cold climate regions, microorganisms in upper layers of soil are subject to low temperatures and repeated freeze-thaw (FT) conditions during the winter. We studied the effects of cold temperature and FT cycles on the viability and survival strategies (namely motility and biofilm formation) of the common soil bacterium and model pathogen Bacillus subtilis. We also examined the effect of FT on the transport behavior of B. subtilis at two solution ionic strengths (IS: 10 and 100 mM) in quartz sand packed columns. Finally, to study the mechanical properties of the bacteria-surface bond, a quartz crystal microbalance with dissipation monitoring (QCM-D) was used to monitor changes in bond stiffness when B. subtilis attached to a quartz substrate (model sand surface) under different environmental conditions. We observed that increasing the number of FT cycles decreased bacterial viability and that B. subtilis survived for longer time periods in higher IS solution. FT treatment decreased bacterial swimming motility and the transcription of flagellin encoding genes. Although FT exposure had no significant effect on the bacterial growth rate, it substantially decreased B. subtilis biofilm formation and correspondingly decreased the transcription of matrix production genes in higher IS solution. As demonstrated with QCM-D, the bond stiffness between B. subtilis and the quartz surface decreased after FT. Moreover, column transport studies showed higher bacterial retention onto sand grains after exposure to FT. This investigation demonstrates how temperature variations around the freezing point in upper layers of soil can influence key bacterial properties and behavior, including survival and subsequent transport.

  6. Learn About GI Motility

    MedlinePlus

    ... Disorders of the Large Intestine Disorders of the Pelvic Floor Motility Testing Personal Stories Contact About GI Motility ... Disorders of the Large Intestine Disorders of the Pelvic Floor Motility Testing Personal Stories Contact About GI Motility ...

  7. About GI Motility

    MedlinePlus

    ... Disorders of the Large Intestine Disorders of the Pelvic Floor Motility Testing Personal Stories Contact About GI Motility ... Disorders of the Large Intestine Disorders of the Pelvic Floor Motility Testing Personal Stories Contact About GI Motility ...

  8. The Proton Coulomb Form Factor from Polarized Inclusive e-p Scattering

    SciTech Connect

    Harris, Christopher Matthew

    2001-05-01

    The proton form factors provide information on the fundamental properties of the proton and provide a test for models based on QCD. In 1998 at Jefferson Lab (JLAB) in Newport News, VA, experiment E93026 measured the inclusive e-p scattering cross section from a polarized ammonia (15NH3) target at a four momentum transfer squared of Q2 = 0.5 (GeV/c)2. Longitudinally polarized electrons were scattered from the polarized target and the scattered electron was detected. Data has been analyzed to obtain the asymmetry from elastically scattered electrons from hydrogen in 15NH3. The asymmetry, Ap, has been used to determine the proton elastic form factor GEp. The result is consistent with the dipole model and data from previous experiments. However, due to the choice of kinematics, the uncertainty in the measurement is large.

  9. Steady film flow over 2D topography with air inclusion formed inside the trench

    NASA Astrophysics Data System (ADS)

    Tsamopoulos, John; Varchanis, Stylianos; Dimakopoulos, Yannis

    2016-11-01

    Liquid film flow along an inclined, solid substrate featuring periodic rectangular trenches may either completely wet the trench floor (Wenzel state) or pin on the entrance and exit corners of the trench (Cassie state) or assume any other configuration in between these two extremes. In the intermediate cases a second gas-liquid interface inside the trench is formed, which adheres to the walls of the trench forming two three-phase contact lines, and encloses a different amount of air under different physical conditions. The Galerkin finite element method is used to solve the Navier-Stokes equations in a physical domain, which is adaptively re-meshed. Multiple steady solutions, connected by turning points and transcritical bifurcations as well as isolated solution branches, are revealed by pseudo arc-length continuation. Two possible cases of a single air inclusion inside the trench are examined. The penetration of the liquid inside the trench is enhanced primarily by increasing either the wettability of the substrate or the capillarity or by decreasing the flow rate. Flow hysteresis may occur when the liquid does not penetrate deep enough inside the trench leading to different flow patterns. The interplay of inertia, viscous, gravity and capillary forces along with substrate wettability determines the volume of the air encapsulated in the trench and the extent of free surface deformation. GSRT of Greece via the program "Excellence" and the LIMMAT foundation.

  10. Ore-forming process of the Huijiabao gold district, southwestern Guizhou Province, China: Evidence from fluid inclusions and stable isotopes

    NASA Astrophysics Data System (ADS)

    Peng, Yiwei; Gu, Xuexiang; Zhang, Yongmei; Liu, Li; Wu, Chengyun; Chen, Siyao

    2014-10-01

    The Huijiabao gold district is one of the major producers for Carlin-type gold deposits in southwestern Guizhou Province, China, including Taipingdong, Zimudang, Shuiyindong, Bojitian and other gold deposits/occurrences. Petrographic observation, microthermometric study and Laser Raman spectroscopy were carried out on the fluid inclusions within representative minerals in various mineralization stages from these four gold deposits. Five types of fluid inclusions have been recognized in hydrothermal minerals of different ore-forming stages: aqueous inclusions, CO2 inclusions, CO2-H2O inclusions, hydrocarbon inclusions, and hydrocarbon-H2O inclusions. The ore-forming fluids are characterized by a H2O + CO2 + CH4 ± N2 system with medium to low temperature and low salinity. From early mineralization stage to later ones, the compositions of the ore-forming fluids experienced an evolution of H2O + NaCl → H2O + NaCl + CO2 + CH4 ± N2 → H2O + NaCl ± CH4 ± CO2 with a slight decrease in homogenization temperature and salinity. The δ18O values of the main-stage quartz vary from 15.2‰ to 24.1‰, while the δDH2O and calculated δ18OH2O values of the ore-forming fluids range from -56.9 to -116.3‰ and from 2.12‰ to 12.7‰, respectively. The δ13CPDB and δ18OSMOW values of hydrothermal calcite change in the range of -9.1‰ to -0.5‰ and 11.1-23.2‰, respectively. Stable isotopic characteristics indicate that the ore-forming fluid was mainly composed of ore- and hydrocarbon-bearing basinal fluid. The dynamic fractionation of the sulfur in the diagenetic pyrite is controlled by bacterial reduction of marine sulfates. The hydrothermal sulfides and the diagenetic pyrite from the host rocks are very similar in their sulfur isotopic composition, suggesting that the sulfur in the ore-forming fluids was mainly derived from dissolution of diagenetic pyrite. The study of fluid inclusions indicates that immiscibility of H2O-NaCl-CO2 fluids took place during the main

  11. Fluorescent labeling reliably identifies Chlamydia trachomatis in living human endometrial cells and rapidly and accurately quantifies chlamydial inclusion forming units.

    PubMed

    Vicetti Miguel, Rodolfo D; Henschel, Kevin J; Dueñas Lopez, Fiorela C; Quispe Calla, Nirk E; Cherpes, Thomas L

    2015-12-01

    Chlamydia replication requires host lipid acquisition, allowing flow cytometry to identify Chlamydia-infected cells that accumulated fluorescent Golgi-specific lipid. Herein, we describe modifications to currently available methods that allow precise differentiation between uninfected and Chlamydia trachomatis-infected human endometrial cells and rapidly and accurately quantify chlamydial inclusion forming units.

  12. Fluorescent labeling reliably identifies Chlamydia trachomatis in living human endometrial cells and rapidly and accurately quantifies chlamydial inclusion forming units

    PubMed Central

    Vicetti Miguel, Rodolfo D.; Henschel, Kevin J.; Dueñas Lopez, Fiorela C.; Quispe Calla, Nirk E.; Cherpes, Thomas L.

    2016-01-01

    Chlamydia replication requires host lipid acquisition, allowing flow cytometry to identify C. trachomatis-infected cells that accumulated fluorescent Golgi-specific lipid. Herein, we describe modifications to currently available methods that allow precise differentiation between uninfected and C. trachomatis-infected human endometrial cells and rapidly and accurately quantify chlamydial inclusion forming units. PMID:26453947

  13. Study to explore the mechanism to form inclusion complexes of β-cyclodextrin with vitamin molecules

    PubMed Central

    Saha, Subhadeep; Roy, Aditi; Roy, Kanak; Roy, Mahendra Nath

    2016-01-01

    Host–guest inclusion complexes of β-cyclodextrin with two vitamins viz., nicotinic acid and ascorbic acid in aqueous medium have been explored by reliable spectroscopic, physicochemical and calorimetric methods as stabilizer, carrier and regulatory releaser of the guest molecules. Job’s plots have been drawn by UV-visible spectroscopy to confirm the 1:1 stoichiometry of the host-guest assembly. Stereo-chemical nature of the inclusion complexes has been explained by 2D NMR spectroscopy. Surface tension and conductivity studies further support the inclusion process. Association constants for the vitamin-β-CD inclusion complexes have been calculated by UV-visible spectroscopy using both Benesi–Hildebrand method and non-linear programme, while the thermodynamic parameters have been estimated with the help of van’t Hoff equation. Isothermal titration calorimetric studies have been performed to determine the stoichiometry, association constant and thermodynamic parameters with high accuracy. The outcomes reveal that there is a drop in ΔSo, which is overcome by higher negative value of ΔHo, making the overall inclusion process thermodynamically favorable. The association constant is found to be higher for ascorbic acid than that for nicotinic acid, which has been explained on the basis of their molecular structures. PMID:27762346

  14. Study to explore the mechanism to form inclusion complexes of β-cyclodextrin with vitamin molecules

    NASA Astrophysics Data System (ADS)

    Saha, Subhadeep; Roy, Aditi; Roy, Kanak; Roy, Mahendra Nath

    2016-10-01

    Host–guest inclusion complexes of β-cyclodextrin with two vitamins viz., nicotinic acid and ascorbic acid in aqueous medium have been explored by reliable spectroscopic, physicochemical and calorimetric methods as stabilizer, carrier and regulatory releaser of the guest molecules. Job’s plots have been drawn by UV-visible spectroscopy to confirm the 1:1 stoichiometry of the host-guest assembly. Stereo-chemical nature of the inclusion complexes has been explained by 2D NMR spectroscopy. Surface tension and conductivity studies further support the inclusion process. Association constants for the vitamin-β-CD inclusion complexes have been calculated by UV-visible spectroscopy using both Benesi–Hildebrand method and non-linear programme, while the thermodynamic parameters have been estimated with the help of van’t Hoff equation. Isothermal titration calorimetric studies have been performed to determine the stoichiometry, association constant and thermodynamic parameters with high accuracy. The outcomes reveal that there is a drop in ΔSo, which is overcome by higher negative value of ΔHo, making the overall inclusion process thermodynamically favorable. The association constant is found to be higher for ascorbic acid than that for nicotinic acid, which has been explained on the basis of their molecular structures.

  15. Extruded foams prepared from high amylose starch with sodium stearate to form amylose inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch foams were prepared from high amylose corn starch in the presence and absence of sodium stearate and PVOH to determine how the formation of amylose-sodium stearate inclusion complexes and the addition of PVOH would affect foam properties. Low extrusion temperatures were used, and X-ray diffra...

  16. Pattern formation in actin gels: A study in the mechanics of gels formed by the important cytoskeletal protein actin, especially as applied to cellular motility

    NASA Astrophysics Data System (ADS)

    Balter, Ariel

    We have studied pattern formation in actin gels to better understand how they function in biological systems, especially in the motility mechanism used by some pathogenic bacteria such as Listeria. By coating themselves with certain enzymes, these bacteria appropriate actin (a protein) from the surrounding host cell's cytoplasm and cause a network or "gel" of actin filaments to grow on their outer surface. As the resulting "comet tail" shaped protrusion grows, it pushes the bacterium away. In experiments, polystyrene beads coated with the same enzymes will also generate comet tails and swim in a very similar manner. However, these bead experiments have also generated anomalous results such as the formation of many comet tails. In some experiments, when two comet tails formed they systematically grew into regular, oppositely handed helices. The formation of any comet tails on a bead poses a physical conundrum. The bacterial enzyme coating is asymmetrical so the comet tail forms in a particular place. But the beads are symmetrical, so comet tails formation constitutes symmetry breaking and spontaneous pattern formation. We have modeled this process as a competition between elastic energy (which favors many tails) and chemical energy (which favors few tails). Our analytical model explains the factors that experimentally determine the number of tails, and numerical simulations confirm these predictions. To understand the helical tails, we did extensive data analysis involving image processing, statistical analysis and mathematical modeling of images of the helical tails. We identified some important features of how the twin tails form. For instance, the tail growth rate is independent of drag force, and bead rotation must accompany helical tail formation. We also created a physical model for helical growth. Numerical simulations of our model show that at very low Reynolds number, a cylindrical object growing under the conditions of an actin comet tail can spontaneously

  17. The hyaluronan receptors CD44 and RHAMM (CD168) form complexeswith ERK1,2, which sustain high basal motility in breast cancercells

    SciTech Connect

    Hamilton, Sara R.; Fard, Shireen F.; Paiwand, Frouz F.; Tolg,Cornelia; Veiseh, Mandana; Wang, Chao; McCarthy, James B.; Bissell, MinaJ.; Koropatnick, James; Turley, Eva A.

    2007-03-28

    CD44 is an integral hyaluronan receptor that can promote or inhibit motogenic signaling in tumor cells. Rhamm is a non-integral cell surface hyaluronan receptor (CD168) and intracellular protein that promotes cell motility in culture and its expression is strongly upregulated in diseases like arthritis and aggressive cancers. Here we describe an autocrine mechanism utilizing cell surface Rhamm/CD44 interactions to sustain rapid basal motility in invasive breast cancer cell lines. This mechanism requires endogenous hyaluronan synthesis and the formation of Rhamm/CD44/ERK1, 2 complexes. Motile/ invasive MDA-MB-231 and Ras-MCF10A cells produce more endogenous hyaluronan, cell surface CD44 and Rhamm, an oncogenic Rhamm isoform, and exhibit elevated basal activation of ERK1, 2 than less invasive MCF7 and MCF10A breast cancer cells. Furthermore, CD44, Rhamm and ERK1, 2 uniquely co-immunoprecipitate and co-localize in MDA-MB-231 and Ras-MCF10A cells. Rapid motility of the invasive cell lines requires interaction of hyaluronan with cells, activation of ERK1, 2 and the participation of both cell surface CD44 and Rhamm. Combinations of anti-CD44, anti-Rhamm antibodies and a MEK1 inhibitor (PD098059) have less-than-additive blocking effects, suggesting action of all three proteins on a common motogenic signaling pathway. Collectively, these results show that cell surface Rhamm and CD44 act together in a hyaluronan-dependent, autocrine mechanism to coordinate sustained signaling through ERK1, 2 leading to high basal motility of invasive breast cancer cells. Since CD44/Rhamm complexes are not evident in less motile cells, an effect of CD44 on tumor cell motility may depend in part on its ability to partner with additional proteins, in this case cell surface Rhamm.

  18. THE HYALURONAN RECEPTORS CD44 AND RHAMM (CD168) FORM COMPLEXES WITH ERK1,2, WHICH SUSTAIN HIGH BASAL MOTILITY IN BREAST CANCER CELLS

    PubMed Central

    Hamilton, Sara R.; Fard, Shireen F.; Paiwand, Frouz F.; Tolg, Cornelia; Veiseh, Mandana; Wang, Chao; McCarthy, James B.; Bissell, Mina J.; Koropatnick, James; Turley, Eva A.

    2010-01-01

    CD44 is an integral hyaluronan receptor that can promote or inhibit motogenic signaling in tumor cells. Rhamm is a non-integral cell surface hyaluronan receptor (CD168) and intracellular protein that promotes cell motility in culture and its expression is strongly upregulated in diseases like arthritis and aggressive cancers. Here we describe an autocrine mechanism utilizing cell surface Rhamm/CD44 interactions to sustain rapid basal motility in invasive breast cancer cell lines. This mechanism requires endogenous hyaluronan synthesis and the formation of Rhamm/CD44/ERK1,2 complexes. Motile/ invasive MDA-MB-231 and Ras-MCF10A cells produce more endogenous hyaluronan, cell surface CD44 and Rhamm, an oncogenic Rhamm isoform, and exhibit elevated basal activation of ERK1,2 than less invasive MCF7 and MCF10A breast cancer cells. Furthermore, CD44, Rhamm and ERK1,2 uniquely co-immunoprecipitate and co-localize in MDA-MB-231 and Ras-MCF10A cells. Rapid motility of the invasive cell lines requires interaction of hyaluronan with cells, activation of ERK1,2 and the participation of both cell surface CD44 and Rhamm. Combinations of anti-CD44, anti-Rhamm antibodies and a MEK1 inhibitor (PD098059) have less-than-additive blocking effects, suggesting action of all three proteins on a common motogenic signaling pathway. Collectively, these results show that cell surface Rhamm and CD44 act together in a hyaluronan-dependent, autocrine mechanism to coordinate sustained signaling through ERK1,2 leading to high basal motility of invasive breast cancer cells. Since CD44/Rhamm complexes are not evident in less motile cells, an effect of CD44 on tumor cell motility may depend in part on its ability to partner with additional proteins, in this case cell surface Rhamm. PMID:17392272

  19. TDP-43 inclusion bodies formed in bacteria are structurally amorphous, non-amyloid and inherently toxic to neuroblastoma cells.

    PubMed

    Capitini, Claudia; Conti, Simona; Perni, Michele; Guidi, Francesca; Cascella, Roberta; De Poli, Angela; Penco, Amanda; Relini, Annalisa; Cecchi, Cristina; Chiti, Fabrizio

    2014-01-01

    Accumulation of ubiquitin-positive, tau- and α-synuclein-negative intracellular inclusions of TDP-43 in the central nervous system represents the major hallmark correlated to amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin-positive inclusions. Such inclusions have variably been described as amorphous aggregates or more structured deposits having an amyloid structure. Following the observations that bacterial inclusion bodies generally consist of amyloid aggregates, we have overexpressed full-length TDP-43 and C-terminal TDP-43 in E. coli, purified the resulting full-length and C-terminal TDP-43 containing inclusion bodies (FL and Ct TDP-43 IBs) and subjected them to biophysical analyses to assess their structure/morphology. We show that both FL and Ct TDP-43 aggregates contained in the bacterial IBs do not bind amyloid dyes such as thioflavin T and Congo red, possess a disordered secondary structure, as inferred using circular dichroism and infrared spectroscopies, and are susceptible to proteinase K digestion, thus possessing none of the hallmarks for amyloid. Moreover, atomic force microscopy revealed an irregular structure for both types of TDP-43 IBs and confirmed the absence of amyloid-like species after proteinase K treatment. Cell biology experiments showed that FL TDP-43 IBs were able to impair the viability of cultured neuroblastoma cells when added to their extracellular medium and, more markedly, when transfected into their cytosol, where they are at least in part ubiquitinated and phosphorylated. These data reveal an inherently high propensity of TDP-43 to form amorphous aggregates, which possess, however, an inherently high ability to cause cell dysfunction. This indicates that a gain of toxic function caused by TDP-43 deposits is effective in TDP-43 pathologies, in addition to possible loss of function mechanisms originating from the cellular mistrafficking of the protein.

  20. TDP-43 Inclusion Bodies Formed in Bacteria Are Structurally Amorphous, Non-Amyloid and Inherently Toxic to Neuroblastoma Cells

    PubMed Central

    Capitini, Claudia; Conti, Simona; Perni, Michele; Guidi, Francesca; Cascella, Roberta; De Poli, Angela; Penco, Amanda; Relini, Annalisa; Cecchi, Cristina; Chiti, Fabrizio

    2014-01-01

    Accumulation of ubiquitin-positive, tau- and α-synuclein-negative intracellular inclusions of TDP-43 in the central nervous system represents the major hallmark correlated to amyotrophic lateral sclerosis and frontotemporal lobar degeneration with ubiquitin-positive inclusions. Such inclusions have variably been described as amorphous aggregates or more structured deposits having an amyloid structure. Following the observations that bacterial inclusion bodies generally consist of amyloid aggregates, we have overexpressed full-length TDP-43 and C-terminal TDP-43 in E. coli, purified the resulting full-length and C-terminal TDP-43 containing inclusion bodies (FL and Ct TDP-43 IBs) and subjected them to biophysical analyses to assess their structure/morphology. We show that both FL and Ct TDP-43 aggregates contained in the bacterial IBs do not bind amyloid dyes such as thioflavin T and Congo red, possess a disordered secondary structure, as inferred using circular dichroism and infrared spectroscopies, and are susceptible to proteinase K digestion, thus possessing none of the hallmarks for amyloid. Moreover, atomic force microscopy revealed an irregular structure for both types of TDP-43 IBs and confirmed the absence of amyloid-like species after proteinase K treatment. Cell biology experiments showed that FL TDP-43 IBs were able to impair the viability of cultured neuroblastoma cells when added to their extracellular medium and, more markedly, when transfected into their cytosol, where they are at least in part ubiquitinated and phosphorylated. These data reveal an inherently high propensity of TDP-43 to form amorphous aggregates, which possess, however, an inherently high ability to cause cell dysfunction. This indicates that a gain of toxic function caused by TDP-43 deposits is effective in TDP-43 pathologies, in addition to possible loss of function mechanisms originating from the cellular mistrafficking of the protein. PMID:24497973

  1. The Teacher as a Significant Part of Inclusive Education in the Conditions of Czech Schools: Current Opinions of Czech Teachers about the Inclusive Form of Education

    ERIC Educational Resources Information Center

    Šmelová, Eva; Ludíková, Libuše; Petrová, Alena; Souralová, Eva

    2016-01-01

    Inclusive education and related aspects are currently the priorities of the educational policy in the Czech Republic. Should inclusion be successful, it needs to be supported not only by public administration authorities and legislation, but also by schools, families, school authorities and counselling services. The present research study analyses…

  2. Secreted or nonsecreted forms of acidic fibroblast growth factor produced by transfected epithelial cells influence cell morphology, motility, and invasive potential.

    PubMed Central

    Jouanneau, J; Gavrilovic, J; Caruelle, D; Jaye, M; Moens, G; Caruelle, J P; Thiery, J P

    1991-01-01

    Addition of exogenous acidic fibroblast growth factor (aFGF) to NBT-II epithelial carcinoma cells results in fibroblastic transformation and cell motility. We have generated aFGF-producing NBT-II cells by transfection with recombinant expression vectors containing human aFGF cDNA, or the human aFGF cDNA coupled to a signal peptide (SP) sequence. The effects of the nonsecreted and the secreted 16-kDa growth factor on the morphology, motility, and cell invasive potential (gelatinase activity) were compared. aFGF coupled to a SP was actively secreted out of the producing cells. The secretion of aFGF was not necessary for induction of gelatinase activity, as this was observed in NBT-II cells producing aFGF with or without SP. Production of aFGF, whether secreted or not secreted, resulted in increased in vitro motility of most isolated clones; however, there was no correlation between aFGF level and motility rate. The data suggest that expression of aFGF in NBT-II cells induces metastatic potential through an autocrine or intracrine mechanism. Images PMID:1707175

  3. A Descriptive Examination of the Types of Relationships Formed between Children with Developmental Disability and Their Closest Peers in Inclusive School Settings

    ERIC Educational Resources Information Center

    Webster, Amanda A.; Carter, Mark

    2013-01-01

    Background: One of the most commonly cited rationales for inclusive education is to enable the development of quality relationships with typically developing peers. Relatively few researchers have examined the features of the range of relationships that children with developmental disability form in inclusive school settings. Method: Interviews…

  4. Effect of different selemethionine forms and levels on performance of breeder hens and se distribution of tissue and egg inclusion.

    PubMed

    Wu, Rujuan; Zhan, Xiuan; Wang, Yongxia; Zhang, Xiwen; Wang, Min; Yuan, Dong

    2011-11-01

    A 2×2 factorial arrangement of treatments in randomized design was conducted to investigate the effect of different selenomethionine (SM) sources and levels on the productive performance of breeder hens and the Se distribution in the inclusion of eggs and serum and tissues of breeder hens and its offspring. A total of 480 Ling-Nan-Huang breeder hens, 48 weeks of age, were allocated to four treatments, each of which included three replicates of 40 hens. Pretreatment period was 2 weeks, and the experiment lasted 8 weeks. Two SM forms of DL-SM and L-SM were supplemented at 0.15 or 0.30 mg Se/kg into the basal diet. Results showed that the Se level of 0.15 mg/kg supplemented in the diet, compared to 0.30 mg/kg, significantly elevated the percentage of egg production (p<0.05), hatchability (p<0.01), and birthrate (p<0.01), whereas the Se level of 0.30 mg/kg led to a higher Se content in egg contents, serum, and all tissues (p<0.01). In addition, the form of DL-SM showed a significant increase in Se content of egg inclusion (p<0.01), serum (p<0.01), and all tissues (p<0.01, except breeder hens' pancreas and its offspring's liver and breast muscle). The birthrate and yolk Se content were markedly influenced by the interaction between Se source and Se level (p<0.01). The above results suggested that DL-SM, compared to L-SM, had a similar equal effect on the performance of breeder hens, but DL-SM was superior to L-SM with respect to selenium distribution in egg inclusion, serum, and tissues.

  5. Inclusion of salt form on prescription medication labeling as a source of patient confusion: a pilot study

    PubMed Central

    McDougall, Dana J.; Hoehns, James D.; Feller, Tara T.; Kriener, Savana J.; Witry, Matthew J.

    2015-01-01

    Background: It has been estimated that 10,000 patient injuries occur in the US annually due to confusion involving drug names. An unexplored source of patient misunderstandings may be medication salt forms. Objective: The objective of this study was to assess patient knowledge and comprehension regarding the salt forms of medications as a potential source of medication errors. Methods: A 12 item questionnaire which assessed patient knowledge of medication names on prescription labels was administered to a convenience sample of patients presenting to a family practice clinic. Descriptive statistics were calculated and multivariate analyses were performed. Results: There were 308 responses. Overall, 41% of patients agreed they find their medication names confusing. Participants correctly answered to salt form questions between 12.1% and 56.9% of the time. Taking more prescription medications and higher education level were positively associated with providing more correct answers to 3 medication salt form knowledge questions, while age was negatively associated. Conclusions: Patient misconceptions about medication salt forms are common. These findings support recommendations to standardize the inclusion or exclusion of salt forms. Increasing patient education is another possible approach to reducing confusion. PMID:27011777

  6. Cellular mechanics and motility

    NASA Astrophysics Data System (ADS)

    Hénon, Sylvie; Sykes, Cécile

    2015-10-01

    The term motility defines the movement of a living organism. One widely known example is the motility of sperm cells, or the one of flagellar bacteria. The propulsive element of such organisms is a cilium(or flagellum) that beats. Although cells in our tissues do not have a flagellum in general, they are still able to move, as we will discover in this chapter. In fact, in both cases of movement, with or without a flagellum, cell motility is due to a dynamic re-arrangement of polymers inside the cell. Let us first have a closer look at the propulsion mechanism in the case of a flagellum or a cilium, which is the best known, but also the simplest, and which will help us to define the hydrodynamic general conditions of cell movement. A flagellum is sustained by cellular polymers arranged in semi-flexible bundles and flagellar beating generates cell displacement. These polymers or filaments are part of the cellular skeleton, or "cytoskeleton", which is, in this case, external to the cellular main body of the organism. In fact, bacteria move in a hydrodynamic regime in which viscosity dominates over inertia. The system is thus in a hydrodynamic regime of low Reynolds number (Box 5.1), which is nearly exclusively the case in all cell movements. Bacteria and their propulsion mode by flagella beating are our unicellular ancestors 3.5 billion years ago. Since then, we have evolved to form pluricellular organisms. However, to keep the ability of displacement, to heal our wounds for example, our cells lost their flagellum, since it was not optimal in a dense cell environment: cells are too close to each other to leave enough space for the flagella to accomplish propulsion. The cytoskeleton thus developed inside the cell body to ensure cell shape changes and movement, and also mechanical strength within a tissue. The cytoskeleton of our cells, like the polymers or filaments that sustain the flagellum, is also composed of semi-flexible filaments arranged in bundles, and also in

  7. The Tobacco etch virus P3 protein forms mobile inclusions via the early secretory pathway and traffics along actin microfilaments.

    PubMed

    Cui, Xiaoyan; Wei, Taiyun; Chowda-Reddy, R V; Sun, Guangyu; Wang, Aiming

    2010-02-05

    Plant potyviruses encode two membrane proteins, 6K and P3. The 6K protein has been shown to induce virus replication vesicles. However, the function of P3 remains unclear. In this study, subcellular localization of the Tobacco etch virus (TEV) P3 protein was investigated in Nicotiana benthamiana leaf cells. The TEV P3 protein localized on the endoplasmic reticulum (ER) membrane and formed punctate inclusions in association with the Golgi apparatus. The trafficking of P3 to the Golgi was mediated by the early secretory pathway. The Golgi-associated punctate structures originated from the ER exit site (ERES). Deletion analyses identified P3 domains required for the retention of P3 at the Golgi. Moreover, the P3 punctate structure was found to traffic along the actin filaments and colocalize with the 6K-containing replication vesicles. Taken together, these data support previous suggestions that P3 may play dual roles in virus movement and replication.

  8. Remelting of refractory inclusions in the chondrule-forming regions: Evidence from chondrule-bearing type C calcium-aluminum-rich inclusions from Allende

    NASA Astrophysics Data System (ADS)

    Krot, Alexander N.; Yurimoto, Hisayoshi; Hutcheon, Ian D.; Chaussidon, Marc; MacPherson, Glenn J.; Paque, Julie

    2007-08-01

    We describe the mineralogy, petrology, oxygen, and magnesium isotope compositions of three coarse-grained, igneous, anorthite-rich (type C) Ca-Al-rich inclusions (CAIs) (ABC, TS26, and 93) that are associated with ferromagnesian chondrule-like silicate materials from the CV carbonaceous chondrite Allende. The CAIs consist of lath-shaped anorthite (An99), Cr-bearing Al-Ti-diopside (Al and Ti contents are highly variable), spinel, and highly åkermanitic and Na-rich melilite (Åk63-74, 0.4-0.6 wt% Na2O). TS26 and 93 lack Wark-Lovering rim layers; ABC is a CAI fragment missing the outermost part. The peripheral portions of TS26 and ABC are enriched in SiO2 and depleted in TiO2 and Al2O3 compared to their cores and contain relict ferromagnesian chondrule fragments composed of forsteritic olivine (Fa6-8) and low-Ca pyroxene/pigeonite (Fs1Wo1-9). The relict grains are corroded by Al-Ti-diopside of the host CAIs and surrounded by haloes of augite (Fs0.5Wo30-42). The outer portion of CAI 93 enriched in spinel is overgrown by coarse-grained pigeonite (Fs0.5-2Wo5-17), augite (Fs0.5Wo38-42), and anorthitic plagioclase (An84). Relict olivine and low-Ca pyroxene/pigeonite in ABC and TS26, and the pigeonite-augite rim around 93 are 16O-poor (Δ17O ˜ -1‰ to -8‰). Spinel and Al-Ti-diopside in cores of CAIs ABC, TS26, and 93 are 16O-enriched (Δ17O down to -20‰), whereas Al-Ti-diopside in the outer zones, as well as melilite and anorthite, are 16O-depleted to various degrees (Δ17O = -11‰ to 2‰). In contrast to typical Allende CAIs that have the canonical initial 26Al/27Al ratio of ˜5 × 10-5 ABC, 93, and TS26 are 26Al-poor with (26Al/27Al)0 ratios of (4.7 ± 1.4) × 10-6 (1.5 ± 1.8) × 10-6 <1.2 × 10-6 respectively. We conclude that ABC, TS26, and 93 experienced remelting with addition of ferromagnesian chondrule silicates and incomplete oxygen isotopic exchange in an 16O-poor gaseous reservoir, probably in the chondrule-forming region. This melting episode could

  9. Inclusion property of Cs, Sr, and Ba impurities in LiCl crystal formed by layer-melt crystallization

    SciTech Connect

    Choi, Jung-Hoon; Cho, Yung-Zun; Lee, Tae-Kyo; Eun, Hee-Chul; Kim, Jun-Hong; Park, Hwan-Seo; Kim, In-Tae; Park, Geun-Il

    2013-07-01

    Pyroprocessing is one of the promising technologies enabling the recycling of spent nuclear fuels from a commercial light water reactor (LWR). In general, pyroprocessing uses dry molten salts as electrolytes. In particular, LiCl waste salt after pyroprocessing contains highly radioactive I/II group fission products mainly composed of Cs, Sr, and Ba impurities. Therefore, it is beneficial to reuse LiCl salt in the pyroprocessing as an electrolyte for economic and environmental issues. Herein, to understand the inclusion property of impurities within LiCl crystal, the physical properties such as lattice parameter change, bulk modulus, and substitution enthalpy of a LiCl crystal having 0-6 at% Cs{sup +} or Ba{sup 2+} impurities under existence of 1 at% Sr{sup 2+} impurity were calculated via the first-principles density functional theory. The substitution enthalpy of LiCl crystals having 1 at% Sr{sup 2+} showed slightly decreased value than those without Sr{sup 2+} impurity. Therefore, through the substitution enthalpy calculation, it is expected that impurities will be incorporated within LiCl crystal as co-existed form rather than as a single component form. (authors)

  10. Effect of a secondary metallurgy technology on the types of forming nonmetallic inclusions and the corrosion resistance of steel

    NASA Astrophysics Data System (ADS)

    Dub, V. S.; Safronov, A. A.; Movchan, M. A.; Ioffe, A. V.; Tazetdinov, V. I.; Zhivykh, G. A.

    2016-12-01

    The effect of a secondary metallurgy technology on the metal quality during the production of lowcarbon corrosion-resistant steels is estimated. The content of a modifier introduced is found to principally influence the types of inclusions and, via them, the corrosion resistance of parts from the metal subjected to deep refining from sulfur and nonmetallic inclusions.

  11. Regulation of flagellar motility during biofilm formation

    PubMed Central

    Guttenplan, Sarah B.; Kearns, Daniel B.

    2013-01-01

    Many bacteria swim in liquid or swarm over solid surfaces by synthesizing rotary flagella. The same bacteria that are motile also commonly form non-motile multicellular aggregates held together by an extracellular matrix called biofilms. Biofilms are an important part of the lifestyle of pathogenic bacteria and it is assumed that there is a motility-to-biofilm transition wherein the inhibition of motility promotes biofilm formation. The transition is largely inferred from regulatory mutants that reveal the opposite regulation of the two phenotypes. Here we review the regulation of motility during biofilm formation in Bacillus, Pseudomonas, Vibrio, and Escherichia, and we conclude that the motility-to-biofilm transition, if necessary, likely involves two steps. In the short term, flagella are functionally regulated to either inhibit rotation or modulate the basal flagellar reversal frequency. Over the long term, flagellar gene transcription is inhibited and in the absence of de novo synthesis, flagella are likely diluted to extinction through growth. Both short term and long term control is likely important to the motility-to-biofilm transition to stabilize aggregates and optimize resource investment. We emphasize the newly discovered classes of flagellar functional regulators and speculate that others await discovery in the context of biofilm formation. PMID:23480406

  12. Phase Structure and Properties of a Biodegradable Block Copolymer Coalesced from It's Crystalline Inclusion Compound Formed with alpha-Cyclodextrin

    NASA Astrophysics Data System (ADS)

    Shuai, Xintao; Wei, Min; Probeni, Francis; Bullions, Todd A.; Shin, I. Daniel; Tonelli, Alan E.

    2002-03-01

    A well-defined biodegradable block copolymer of poly(epsilon caprolactone) (PCL) and poly(L-lactic acid) (PLLA) was synthesized and characterized and then included as a guest in an inclusion compound (IC) formed with the host alpha-cyclodextrin (CD). The PCL-b-PLLA block copolymer was subsequently coalesced from it's CD-IC crystals by either treatment with hot water (50 C) or an aqueous amylase solution at 25 C. The coalesced PCL-b-PLLA was examined by FTIR, DSC, TGA, and WAXD and was found to be much more homogeneosly organized, with much less segregation and crystallinity of the PCL and PLLA microphases. The morpholgy, crystallization kinetics, thermal behavior, and biodegradability of the coalesced PCL-b-PLLA block copolymer was studied by comparison to similar observations made on as-synthesized PCL-b-PLLA, PCL and PLLA homopolymers, and their solution-cast blend. The PCL and PLLA blocks are found to be more intimately mixed, with less phase segregation, in the coalesced diblock copolymer, and this leads to homogeneous bulk crystallization, which is not observed for the as-synthesized diblock copolymer. The coalesced PCL-b-PLLA was also found to be more quickly biodegraded (lipase from Rhizopus arrhizus)than the as-synthesized PCL-b-PLLA or the physical blend of PCL and PLLA homopolymers. Overall, the coalescence of the inherently phase segregated diblock copolymer PCL-b-PLLA results in a small amount of compact, chain-extended PCL and PLLA crystals embedded in an amorphous phase, largely consisting of well-mixed PCL and PLLA blocks. Thus, we have demonstrated that it is possible to control the morpholgy of a biodegradable diblock copolymer, thereby significantly modifying it's properties, by coalescence from it's CD-IC crystals.

  13. The morphology of Al-Ti-O complex oxide inclusions formed in an ultra low-carbon steel melt during the RH process

    NASA Astrophysics Data System (ADS)

    Doo, Won-Chul; Kim, Dong-Yong; Kang, Soo-Chang; Yi, Kyung-Woo

    2007-06-01

    Internal morphologies of bulk shape oxides in a melt of Ti bearing low-carbon steel were analyzed. The outer shapes of nearly spherical inclusions containing Ti were quite different from the shape of alumina inclusions that typically have a cluster form. A cross-section investigation using a polishing method and the FIB method revealed that the TiOx-Al2O3 complex oxide covers alumina clusters and that the interfaces of the alumina and complex oxide are modified as time passes.

  14. Mouse infection and pathogenesis by Trypanosoma brucei motility mutants.

    PubMed

    Kisalu, Neville K; Langousis, Gerasimos; Bentolila, Laurent A; Ralston, Katherine S; Hill, Kent L

    2014-06-01

    The flagellum of Trypanosoma brucei is an essential and multifunctional organelle that drives parasite motility and is receiving increased attention as a potential drug target. In the mammalian host, parasite motility is suspected to contribute to infection and disease pathogenesis. However, it has not been possible to test this hypothesis owing to lack of motility mutants that are viable in the bloodstream life cycle stage that infects the mammalian host. We recently identified a bloodstream-form motility mutant in 427-derived T. brucei in which point mutations in the LC1 dynein subunit disrupt propulsive motility but do not affect viability. These mutants have an actively beating flagellum, but cannot translocate. Here we demonstrate that the LC1 point mutant fails to show enhanced cell motility upon increasing viscosity of the surrounding medium, which is a hallmark of wild type T. brucei, thus indicating that motility of the mutant is fundamentally altered compared with wild type cells. We next used the LC1 point mutant to assess the influence of trypanosome motility on infection in mice. Wesurprisingly found that disrupting parasite motility has no discernible effect on T. brucei bloodstream infection. Infection time-course, maximum parasitaemia, number of waves of parasitaemia, clinical features and disease outcome are indistinguishable between motility mutant and control parasites. Our studies provide an important step toward understanding the contribution of parasite motility to infection and a foundation for future investigations of T. brucei interaction with the mammalian host.

  15. The effect of the inclusion of recycled poultry bedding and the physical form of diet on the performance, ruminal fermentation, and plasma metabolites of fattening lambs.

    PubMed

    Mirmohammadi, D; Rouzbehan, Y; Fazaeli, H

    2015-08-01

    During a 125-d experimental period, 24 Afshari × Kurdish male lambs initially weighing 25.2 ± 1.2 kg were grouped by BW and randomly assigned to treatments under a completely randomized design with a 2 × 2 factorial arrangement of treatments to evaluate the effects of feeding recycled poultry bedding (RPB; 0 and 200 g/kg DM) and the physical form of the diet (mash and block) on nutrient intake and digestibility, ruminal and plasma parameters, microbial N supply, N balance, feeding behavior, and growth performance of the lambs. Two diets with and without RPB in both mash and block form were prepared. Neither the inclusion of RPB nor the physical form of the diet affected the concentration of VFA or the total tract apparent digestibility of nutrients. Dietary RPB inclusion increased DMI ( < 0.01), tended ( = 0.10) to reduce ADG, and decreased G:F ( = 0.05). The physical form of the diet had no effect on DMI but decreased ADG ( = 0.01) and G:F ( = 0.02) in lambs fed on the block diet compared with those fed on the mash diet. Neither the inclusion of RPB nor the physical form of the diets had any effect on microbial N supply (g/d) and N retention. Rate of eating ( = 0.07), time spent eating ( = 0.87) and ruminating ( = 0.28), and total chewing activity ( = 0.65) were not affected by dietary RPB inclusion. Rate of eating decreased ( < 0.01) and time spent eating and total chewing activity increased ( = 0.01 and = 0.02, respectively) in lambs fed on the block diet compared with those fed on the mash diet. Results of the current study showed that inclusion of RPB up to 200 g/kg DM in diets for fattening was possible without any effect on performance and animal health. Processing of feed into the mash form gave higher livestock productivity in comparison to the block form.

  16. The fibrous form of intracellular inclusion bodies in recombinant variant fibrinogen-producing cells is specific to the hepatic fibrinogen storage disease-inducible variant fibrinogen.

    PubMed

    Arai, Shinpei; Ogiwara, Naoko; Mukai, Saki; Takezawa, Yuka; Sugano, Mitsutoshi; Honda, Takayuki; Okumura, Nobuo

    2017-02-04

    Fibrinogen storage disease (FSD) is a rare disorder that is characterized by the accumulation of fibrinogen in hepatocytes and induces liver injury. Six mutations in the γC domain (γG284R, γT314P, γD316N, the deletion of γG346-Q350, γG366S, and γR375W) have been identified for FSD. Our group previously established γ375W fibrinogen-producing Chinese hamster ovary (CHO) cells and observed aberrant large granular and fibrous forms of intracellular inclusion bodies. The aim of this study was to investigate whether fibrous intracellular inclusion bodies are specific to FSD-inducible variant fibrinogen. Thirteen expression vectors encoding the variant γ-chain were stably or transiently transfected into CHO cells expressing normal fibrinogen Aα- and Bβ-chains or HuH-7 cells, which were then immunofluorescently stained. Six CHO and HuH-7 cell lines that transiently produced FSD-inducible variant fibrinogen presented the fibrous (3.2-22.7 and 2.1-24.5%, respectively) and large granular (5.4-25.5 and 7.7-23.9%) forms of intracellular inclusion bodies. Seven CHO and HuH-7 cell lines that transiently produced FSD-non-inducible variant fibrinogen only exhibit the large granular form. These results demonstrate that transiently transfected variant fibrinogen-producing CHO cells and inclusion bodies of the fibrous form may be useful in non-invasive screening for FSD risk factors for FSD before its onset.

  17. Origin of spinel lamella and/or inclusions in olivine of harzburgite form the Pauza ultramafic rocks from the Kurdistan region, northeastern Iraq

    NASA Astrophysics Data System (ADS)

    Mohammad, Y.; Maekawa, H.; Karim, K.

    2009-04-01

    Exsolution lamellae and octahedral inclusions of chromian spinel occur in olivine of harzburgite of the Pauza ultramafic rocks, Kurdistan region, northeastern Iraq. The lamella is up to 80μm long and up to 50 μm wide. The lamellae and octahedral inclusions of chromian spinel are distributed heterogeneously in the host olivine crystal. They are depleted in Al2O3 relative to the subhedral spinel grains in the matrix and spinel lamella in orthopyroxene. Olivine (Fo92 - 93) with spinel lamellae occurs as fine-grained crystals around orthopyroxene, whereas olivine (Fo90-91) free from spinel is found in matrix. Based on back-scattered images analyses, enrichments of both Cr # and Fe+3 in the chromian spinel lamella in olivine (replacive olivine) relative to that in adjacent orthopyroxene. As well as the compositions of chromian spinel lamellae host olivine are more Mg-rich than the matrix olivine. Furthermore the restriction of olivine with spinel lamellae and octahedral inclusions on around orthopyroxene, and the similarity of spinel lamella orientations in both olivine and adjacent orthopyroxene. This study concludes that the spinel inclusions in olivine are remnant (inherited from former orthopyroxene) spinel exsolution lamella in orthopyroxene, that has been formed in upper mantle conditions ( T = 1200 °C, P = 2.5 GPa ). Replacive olivine are formed by reaction of ascending silica poor melt and orthopyroxene in harzburgite as pressure decrease the solubility of silica-rich phase (orthopyroxene) in the system increase, therefore ascending melt dissolve pyroxene with spinel exsolution lamella and precipitate replacive olivine with spinel inclusions. We can conclude that the olivines with spinel lamella are not necessary to be original and presenting ultrahigh-pressure and/or ultra deep-mantle conditions as previously concluded. It has been formed by melting of orthopyroxene (orthopyroxene with spinel exsolution lamella = olivine with spinel lamellae and octahedral

  18. Sperm Motility in Flow

    NASA Astrophysics Data System (ADS)

    Guasto, Jeffrey; Juarez, Gabriel; Stocker, Roman

    2012-11-01

    A wide variety of plants and animals reproduce sexually by releasing motile sperm that seek out a conspecific egg, for example in the reproductive tract for mammals or in the water column for externally fertilizing organisms. Sperm are aided in their quest by chemical cues, but must also contend with hydrodynamic forces, resulting from laminar flows in reproductive tracts or turbulence in aquatic habitats. To understand how velocity gradients affect motility, we subjected swimming sperm to a range of highly-controlled straining flows using a cross-flow microfluidic device. The motion of the cell body and flagellum were captured through high-speed video microscopy. The effects of flow on swimming are twofold. For moderate velocity gradients, flow simply advects and reorients cells, quenching their ability to cross streamlines. For high velocity gradients, fluid stresses hinder the internal bending of the flagellum, directly inhibiting motility. The transition between the two regimes is governed by the Sperm number, which compares the external viscous stresses with the internal elastic stresses. Ultimately, unraveling the role of flow in sperm motility will lead to a better understanding of population dynamics among aquatic organisms and infertility problems in humans.

  19. An animated model of reticulorumen motility.

    PubMed

    Gookin, Jody L; Foster, Derek M; Harvey, Alice M; McWhorter, Dan

    2009-01-01

    Understanding reticulorumen motility is important to the assessment of ruminant health and optimal production, and in the recognition, diagnosis, and treatment of disease. Accordingly, the teaching of reticulorumen motility is a staple of all veterinary curricula. This teaching has historically been based on written descriptions, line drawings, or pressure tracings obtained during contraction sequences. We developed an animated model of reticulorumen motility and hypothesized that veterinary students would prefer use of the model over traditional instructional methods. First-year veterinary students were randomly allocated to one of two online learning exercises: with the animated model (Group A) or with text and line drawings (Group B) depicting reticulorumen motility. Learning was assessed with a multiple-choice quiz and feedback on the learning alternatives was obtained by survey. Seventy-four students participated in the study, including 38/42 in Group A and 36/36 in Group B. Sixty-four out of 72 students (89%) responded that they would prefer use of the animated model if only one of the two learning methods was available. A majority of students agreed or strongly agreed that the animated model was easy to understand and improved their knowledge and appreciation of the importance of reticulorumen motility, and would recommend the model to other veterinary students. Interestingly, students in Group B achieved higher scores on examination than students in Group A. This could be speculatively attributed to the inclusion of an itemized list of contraction sequences in the text provided to Group B and failure of Group A students to read the text associated with the animations.

  20. Source and evolution of ore-forming hydrothermal fluids in the northern Iberian Pyrite Belt massive sulphide deposits (SW Spain): evidence from fluid inclusions and stable isotopes

    NASA Astrophysics Data System (ADS)

    Sánchez-España, Javier; Velasco, Francisco; Boyce, Adrian J.; Fallick, Anthony E.

    2003-08-01

    A fluid inclusion and stable isotopic study has been undertaken on some massive sulphide deposits (Aguas Teñidas Este, Concepción, San Miguel, San Telmo and Cueva de la Mora) located in the northern Iberian Pyrite Belt. The isotopic analyses were mainly performed on quartz, chlorite, carbonate and whole rock samples from the stockworks and altered footwall zones of the deposits, and also on some fluid inclusion waters. Homogenization temperatures of fluid inclusions in quartz mostly range from 120 to 280 °C. Salinity of most fluid inclusions ranges from 2 to 14 wt% NaCl equiv. A few cases with Th=80-110 °C and salinity of 16-24 wt% NaCl equiv., have been also recognized. In addition, fluid inclusions from the Soloviejo Mn-Fe-jaspers (160-190 °C and ≈6 wt% NaCl equiv.) and some Late to Post-Hercynian quartz veins (130-270 °C and ≈4 wt% NaCl equiv.) were also studied. Isotopic results indicate that fluids in equilibrium with measured quartz (δ18Ofluid ≈-2 to 4‰), chlorites (δ18Ofluid ≈8-14‰, δDfluid ≈-45 to -27‰), whole rocks (δ18Ofluid ≈4-7‰, δDfluid ≈-15 to -10‰), and carbonates (δ18Oankerite ≈14.5-16‰, δ13Cfluid =-11 to -5‰) evolved isotopically during the lifetime of the hydrothermal systems, following a waxing/waning cycle at different temperatures and water/rock ratios. The results (fluid inclusions, δ18O, δD and δ13C values) point to a highly evolved seawater, along with a variable (but significant) contribution of other fluid reservoirs such as magmatic and/or deep metamorphic waters, as the most probable sources for the ore-forming fluids. These fluids interacted with the underlying volcanic and sedimentary rocks during convective circulation through the upper crust.

  1. Motility of Mollicutes

    NASA Astrophysics Data System (ADS)

    Wolgemuth, Charles; Igoshin, Oleg; Oster, George

    2003-03-01

    Recent experiments show that the conformation of filament proteins play a role in the motility and morphology of many different types of bacteria. Conformational changes in the protein subunits may produce forces to drive propulsion and cell division. Here we present a molecular mechanism by which these forces can drive cell motion. Coupling of a biochemical cycle, such as ATP hydrolysis, to the dynamics of elastic filaments enable elastic filaments to propagate deformations that generate propulsive forces. We demonstrate this possibility for two classes of wall-less bacteria called mollicutes: the swimming of helical shaped Spiroplasma, and the gliding motility of Mycoplasma. Similar mechanisms may explain the locomotion of other prokaryotes, including the swimming of Synechococcus and the gliding of some myxobacteria.

  2. Modeling collective cell motility

    NASA Astrophysics Data System (ADS)

    Rappel, Wouter-Jan

    Eukaryotic cells often move in groups, a critical aspect of many biological and medical processes including wound healing, morphogenesis and cancer metastasis. Modeling can provide useful insights into the fundamental mechanisms of collective cell motility. Constructing models that incorporate the physical properties of the cells, however, is challenging. Here, I discuss our efforts to build a comprehensive cell motility model that includes cell membrane properties, cell-substrate interactions, cell polarity, and cell-cell interaction. The model will be applied to a variety of systems, including motion on micropatterned substrates and the migration of border cells in Drosophila. This work was supported by NIH Grant No. P01 GM078586 and NSF Grant No. 1068869.

  3. NCAM regulates cell motility.

    PubMed

    Prag, Søren; Lepekhin, Eugene A; Kolkova, Kateryna; Hartmann-Petersen, Rasmus; Kawa, Anna; Walmod, Peter S; Belman, Vadym; Gallagher, Helen C; Berezin, Vladimir; Bock, Elisabeth; Pedersen, Nina

    2002-01-15

    Cell migration is required during development of the nervous system. The regulatory mechanisms for this process, however, are poorly elucidated. We show here that expression of or exposure to the neural cell adhesion molecule (NCAM) strongly affected the motile behaviour of glioma cells independently of homophilic NCAM interactions. Expression of the transmembrane 140 kDa isoform of NCAM (NCAM-140) caused a significant reduction in cellular motility, probably through interference with factors regulating cellular attachment, as NCAM-140-expressing cells exhibited a decreased attachment to a fibronectin substratum compared with NCAM-negative cells. Ectopic expression of the cytoplasmic part of NCAM-140 also inhibited cell motility, presumably via the non-receptor tyrosine kinase p59(fyn) with which NCAM-140 interacts. Furthermore, we showed that the extracellular part of NCAM acted as a paracrine inhibitor of NCAM-negative cell locomotion through a heterophilic interaction with a cell-surface receptor. As we showed that the two N-terminal immunoglobulin modules of NCAM, which are known to bind to heparin, were responsible for this inhibition, we presume that this receptor is a heparan sulfate proteoglycan. A model for the inhibitory effect of NCAM is proposed, which involves competition between NCAM and extracellular components for the binding to membrane-associated heparan sulfate proteoglycan.

  4. Motility of Mycoplasma pneumoniae.

    PubMed Central

    Radestock, U; Bredt, W

    1977-01-01

    Cell of Mycoplasma pneumoniae FH gliding on a glass surface in liquid medium were examined by microscopic observation and quantitatively by microcinematography (30 frames per min). Comparisons were made only within the individual experiments. The cells moved in an irregular pattern with numerous narrow bends and circles. They never changed their leading end. The average speed (without pauses) was relatively constant between o.2 and 0.5 mum/s. The maximum speed was about 1.5 to 2.0 mum/s. The movements were interrupted by resting periods of different lengths and frequency. Temperature, viscosity, pH, and the presence of yeast extract in the medium influenced the motility significantly; changes in glucose, calcium ions, and serum content were less effective. The movements were affected by iodoacetate, p-mercuribenzoate, and mitomycin C at inhibitory or subinhibitory concentrations. Sodium fluoride, sodium cyanide, dinitrophenol, chloramphenicol, puromycin, cholchicin, and cytochalasin B at minimal inhibitory concentrations did not affect motility. The movements were effectively inhibited by anti-M. pneumoniae antiserum. Studies with absorbed antiserum suggested that the surface components involved in motility are heat labile. The gliding of M. pneumoniae cells required an intact energy metabolism and the proteins involved seemed to have a low turnover. Images PMID:14925

  5. Cell Motility Resulting form Spontaneous Polymerization Waves

    NASA Astrophysics Data System (ADS)

    Kruse, Karsten

    2014-03-01

    The crawling of living cells on solid substrates is often driven by the actin cytoskeleton, a network of structurally polar filamentous proteins that is intrinsically driven by the hydrolysis of ATP. How cells organize their actin network during crawling is still poorly understood. A possible general mechanism underlying actin organization has been offered by the observation of spontaneous actin polymerization waves in various different cell types. We use a theoretical approach to investigate the possible role of spontaneous actin waves on cell crawling. To this end, we develop a meanfield framework for studying spatiotemporal aspects of actin assembly dynamics, which helped to identify possible origins of self-organized actin waves. The impact of these waves on cell crawling is then investigated by using a phase-field approach to confine the actin network to a cellular domain. We find that spontaneous actin waves can lead to directional or amoeboidal crawling. In the latter case, the cell performs a random walk. Within our deterministic framework, this behavior is due to complex spiral waves inside the cell. Finally, we compare the seemingly random motion of our model cells to the dynamics of cells of the human immune system. These cells patrol the body in search for infected cells and we discuss possible implications of our theory for the search process' efficiency. Work was funded by the DFG through KR3430/1, GK1276, and SFB 1027.

  6. Productive performance of brown-egg laying pullets from hatching to 5 weeks of age as affected by fiber inclusion, feed form, and energy concentration of the diet.

    PubMed

    Guzmán, P; Saldaña, B; Mandalawi, H A; Pérez-Bonilla, A; Lázaro, R; Mateos, G G

    2015-02-01

    The effects of fiber inclusion, feed form, and energy concentration of the diet on the growth performance of pullets from hatching to 5 wk age were studied in 2 experiments. In Experiment 1, there was a control diet based on cereals and soybean meal, and 6 extra diets that included 2 or 4% of cereal straw, sugar beet pulp (SBP), or sunflower hulls (SFHs) at the expense (wt/wt) of the whole control diet. From hatching to 5 wk age fiber inclusion increased (P<0.05) ADG and ADFI, and improved (P<0.05) energy efficiency (EnE; kcal AMEn/g ADG), but body weight (BW) uniformity was not affected. Pullets fed SFH tended to have higher ADG than pullets fed SBP (P=0.072) with pullets fed straw being intermediate. The feed conversion ratio (FCR) was better (P<0.05) with 2% than with 4% fiber inclusion. In Experiment 2, 10 diets were arranged as a 2×5 factorial with 2 feed forms (mash vs. crumbles) and 5 levels of AMEn (2,850, 2,900, 2,950, 3,000, and 3,050 kcal/kg). Pullets fed crumbles were heavier and had better FCR than pullets fed mash (P<0.001). An increase in the energy content of the crumble diets reduced ADFI and improved FCR linearly, but no effects were detected with the mash diets (P<0.01 and P<0.05 for the interactions). Feeding crumbles tended to improve BW uniformity at 5 wk age (P=0.077) but no effects were detected with increases in energy concentration of the diet. In summary, the inclusion of moderate amounts of fiber in the diet improves pullet performance from hatching to 5 wk age. The response of pullets to increases in energy content of the diet depends on feed form with a decrease in feed intake when fed crumbles but no changes when fed mash. Feeding crumbles might be preferred to feeding mash in pullets from hatching to 5 wk age.

  7. Symmetry-Breaking Motility

    NASA Astrophysics Data System (ADS)

    Lee, Allen; Lee, Ha Youn; Kardar, Mehran

    2005-09-01

    Locomotion of bacteria by actin polymerization and in vitro motion of spherical beads coated with a protein catalyzing polymerization are examples of active motility. Starting from a simple model of forces locally normal to the surface of a bead, we construct a phenomenological equation for its motion. The singularities at a continuous transition between moving and stationary beads are shown to be related to the symmetries of its shape. Universal features of the phase behavior are calculated analytically and confirmed by simulations. Fluctuations in velocity are shown to be generically non-Maxwellian and correlated to the shape of the bead.

  8. Evolutionary aspects of collective motility in pathogenic bacteria

    NASA Astrophysics Data System (ADS)

    Deforet, Maxime; Xavier, Joao

    Pseudomonas aeruginosa is a pathogenic bacteria that can use its single polar flagellum to swim through liquids. It can move collectively over semisolid surfaces, a behavior called swarming. It can also settle and form surface-attached communities called biofilms that protect them from antibiotics. The transition from single motility (swimming) to collective motility (swarming) is biologically relevant as it enables exploring environments that a single bacterium cannot explore on its own. It is also clinically relevant since swarming and biofilm formation are thought to be antagonistic. We investigate the mechanisms of bacterial collective motility using a multidisciplinary approach that combines mathematical modeling, quantitative experiments, and microbial genetics. We aim to identify how these mechanisms may evolve under the selective pressure of population expansion, and consequently reinforce or hinder collective motility. In particular, we clarify the role of growth rate and motility in invasive populations.

  9. Novel inclusion in laser crystals

    SciTech Connect

    Ma Xiaoshan; Wang Siting; Jin Zhongru; Shen Yafang; Chen Jiaguang

    1986-12-01

    In growing alexandrite crystals, a novel inclusion has been found. The inclusions are quantitatively analyzed by an electronic probe and the mechanism for forming inclusions is suggested. In our Bridgman MgF/sub 2/ crystals, the inclusions in <001> direction have also been observed.

  10. Motility recovery during the process of regeneration in freshwater planarians.

    PubMed

    Kato, Chihiro; Mihashi, Koshin; Ishida, Sachiko

    2004-04-02

    Planarians are phylogenetically considered to be the most primitive animals to have acquired a central nervous system and a bilateral symmetry. However, very little is known about the relationship between planarian brain integration and motility. A behavioural and histological study was therefore undertaken in an aspect of planarian motility recovery during its process of regeneration. Quantitative analysis showed that the tail-regenerates recovered their motility gradually as the new heads reformed, while the non-head reforming tail fragments showed no signs of recovery. The head fragments recovered their motility soon after cutting. The cephalic margin was not a function of the motility. The brain regenerated back to its original form in approximately two weeks, the same amount of time it took for the decapitated tails to recover their motility to initial levels. This study provides quantitative evidence that the planarian motility recovered in relation to the head formation during its process of regeneration. Our results reinforce the view that the brain plays a functional part in activating planarian motility.

  11. Spirochete motility and morpholgy

    NASA Astrophysics Data System (ADS)

    Charon, Nyles

    2004-03-01

    Spirochetes have a unique structure, and as a result their motility is different from that of other bacteria. These organisms can swim in a highly viscous, gel-like medium, such as that found in connective tissue, that inhibits the motility of most other bacteria. In spirochetes, the organelles for motility, the periplasmic flagella, reside inside the cell within the periplasmic space. A given periplasmic flagellum is attached only at one end of the cell, and depending on the species, may or may not overlap in the center of the cell. The number of periplasmic flagella varies from species to species. These structures have been shown to be directly involved in motility and function by rotating within the periplasmic space (1). The present talk focuses on the spirochete that causes Lyme disease, Borrelia burgdorferi. In many bacterial species, cell shape is usually dictated by the peptidoyglycan layer of the cell wall. In the first part of the talk, results will be presented that the morphology of B. burgdorferi is the result of a complex interaction between the cell cylinder and the internal periplasmic flagella resulting in a cell with a flat-wave morphology. Backward moving, propagating waves enable these bacteria to swim and translate in a given direction. Using targeted mutagenesis, we inactivated the gene encoding the major periplasmic flagellar filament protein FlaB. The resulting flaB mutants not only were non-motile, but were rod-shaped (2). Western blot analysis indicated that flaB was no longer synthesized, and electron microscopy revealed that the mutants were completely deficient in periplasmic flagella. Our results indicate that the periplasmic flagella of B. burgdorferi have a skeletal function. These organelles dynamically interact with the rod-shaped cell cylinder to enable the cell to swim, and to confer in part its flat-wave morphology The latter part of the talk concerns the basis for asymmetrical rotation of the periplasmic flagella of B

  12. Mechanics of motility initiation and motility arrest in crawling cells

    NASA Astrophysics Data System (ADS)

    Recho, Pierre; Putelat, Thibaut; Truskinovsky, Lev

    2015-11-01

    Motility initiation in crawling cells requires transformation of a symmetric state into a polarized state. In contrast, motility arrest is associated with re-symmetrization of the internal configuration of a cell. Experiments on keratocytes suggest that polarization is triggered by the increased contractility of motor proteins but the conditions of re-symmetrization remain unknown. In this paper we show that if adhesion with the extra-cellular substrate is sufficiently low, the progressive intensification of motor-induced contraction may be responsible for both transitions: from static (symmetric) to motile (polarized) at a lower contractility threshold and from motile (polarized) back to static (symmetric) at a higher contractility threshold. Our model of lamellipodial cell motility is based on a 1D projection of the complex intra-cellular dynamics on the direction of locomotion. In the interest of analytical transparency we also neglect active protrusion and view adhesion as passive. Despite the unavoidable oversimplifications associated with these assumptions, the model reproduces quantitatively the motility initiation pattern in fish keratocytes and reveals a crucial role played in cell motility by the nonlocal feedback between the mechanics and the transport of active agents. A prediction of the model that a crawling cell can stop and re-symmetrize when contractility increases sufficiently far beyond the motility initiation threshold still awaits experimental verification.

  13. The effect of flagellar motor-rotor complexes on twitching motility in P. aeruginosa

    NASA Astrophysics Data System (ADS)

    Zhao, Kun; Utada, Andrew; Gibiansky, Maxsim; Xian, Wujing; Wong, Gerard

    2013-03-01

    P. aeruginosa is an opportunistic bacterium responsible for a broad range of biofilm infections. In order for biofilms to form, P. aeruginosa uses different types of surface motility. In the current understanding, flagella are used for swarming motility and type IV pili are used for twitching motility. The flagellum also plays important roles in initial surface attachment and in shaping the architectures of mature biofilms. Here we examine how flagella and pili interact during surface motility, by using cell tracking techniques. We show that the pili driven twitching motility of P. aeruginosa can be affected by the motor-rotor complexes of the flagellar system.

  14. Flagella-independent surface motility in Salmonella enterica serovar Typhimurium

    PubMed Central

    Park, Sun-Yang; Pontes, Mauricio H.; Groisman, Eduardo A.

    2015-01-01

    Flagella are multiprotein complexes necessary for swimming and swarming motility. In Salmonella enterica serovar Typhimurium, flagella-mediated motility is repressed by the PhoP/PhoQ regulatory system. We now report that Salmonella can move on 0.3% agarose media in a flagella-independent manner when experiencing the PhoP/PhoQ-inducing signal low Mg2+. This motility requires the PhoP-activated mgtA, mgtC, and pagM genes, which specify a Mg2+ transporter, an inhibitor of Salmonella’s own F1Fo ATPase, and a small protein of unknown function, respectively. The MgtA and MgtC proteins are necessary for pagM expression because pagM mRNA levels were lower in mgtA and mgtC mutants than in wild-type Salmonella, and also because pagM expression from a heterologous promoter rescued motility in mgtA and mgtC mutants. PagM promotes group motility by a surface protein(s), as a pagM-expressing strain conferred motility upon a pagM null mutant, and proteinase K treatment eliminated motility. The pagM gene is rarely found outside subspecies I of S. enterica and often present in nonfunctional allelic forms in organisms lacking the identified motility. Deletion of the pagM gene reduced bacterial replication on 0.3% agarose low Mg2+ media but not in low Mg2+ liquid media. Our findings define a form of motility that allows Salmonella to scavenge nutrients and to escape toxic compounds in low Mg2+ semisolid environments. PMID:25624475

  15. Rimonabant, Gastrointestinal Motility and Obesity

    PubMed Central

    Sun, Yan; Chen, Jiande

    2012-01-01

    Background: Obesity and overweight affect more than half of the US population and are associated with a number of diseases. Rimonabant, a cannabinoid receptor 1 blocker in the endocannabinoid (EC) system, was indicated in Europe for the treatment of obesity and overweight patients with associated risk factors but withdrawn on Jan, 2009 because of side effects. Many studies have reported the effects of rimonabant on gastrointestinal (GI) motility and food intake. The aims of this review are: to review the relationship of EC system with GI motility and food intake;to review the studies of rimonabant on GI motility, food intake and obesity;and to report the tolerance and side effects of rimonabant. Methods: the literature (Pubmed database) was searched using keywords: rimonabant, obesity and GI motility. Results: GI motility is related with appetite, food intake and nutrients absorption. The EC system inhibits GI motility, reduces emesis and increases food intake; Rimonabant accelerates gastric emptying and intestinal transition but decreases energy metabolism and food intake. There is rapid onset of tolerance to the prokinetic effect of rimonabant. The main side effects of rimonabant are depression and GI symptoms. Conclusions: Rimonabant has significant effects on energy metabolism and food intake, probably mediated via its effects on GI motility. PMID:23449551

  16. A novel 1:1 canal inclusion network formed by deoxycholic acid dimers (bislactones) with benzene molecules: an x-ray study

    NASA Astrophysics Data System (ADS)

    Stanković, S.; Kálmán, A.; Argay, Gy.; Miljković, D.; Kuhajda, K.; Vicković, I.; Bruwo, M.; Ori, O.

    1990-04-01

    A novel canal inclusion network formed by 3α-hydroxy-5β-cholano-12α-24-bislactone (C 48H 74O 6) with benzene molecule (1:1) in a triclinic crystal lattice has been revealed by X-ray diffraction and 1H NMR spectroscopy. Crystal symmetry P1 with a=15.036(4), b=13.269(4), c=7.196(4) Å, α=78.16(2), β=73.42(2), γ=66.42(2) °, Z=1 (one pair of deoxycholic acid (DCA) dimer and benzene in the unit cell) and Dc=1.091 g cm -3. The structure was refined to R 0.082 for 3083 reflections. The DCA dimers separated by unit translations form infinite canals along the shortest axis c. These hydrophobic canals accommodate the benzene molecules separated by a distance of 4.55(2) Å. In accordance with the vigorous thermal motion of the ring atoms the benzene molecules are bound by weak dispersion forces to the host molecules. However, atom—atom potential calculations indicate that the position and orientation of the benzene ring in the void represent the energy minimum.

  17. Cyclic GMP and Cilia Motility

    PubMed Central

    Wyatt, Todd A.

    2015-01-01

    Motile cilia of the lungs respond to environmental challenges by increasing their ciliary beat frequency in order to enhance mucociliary clearance as a fundamental tenant of innate defense. One important second messenger in transducing the regulable nature of motile cilia is cyclic guanosine 3′,5′-monophosphate (cGMP). In this review, the history of cGMP action is presented and a survey of the existing data addressing cGMP action in ciliary motility is presented. Nitric oxide (NO)-mediated regulation of cGMP in ciliated cells is presented in the context of alcohol-induced cilia function and dysfunction. PMID:26264028

  18. Soft micromachines with programmable motility and morphology.

    PubMed

    Huang, Hen-Wei; Sakar, Mahmut Selman; Petruska, Andrew J; Pané, Salvador; Nelson, Bradley J

    2016-07-22

    Nature provides a wide range of inspiration for building mobile micromachines that can navigate through confined heterogenous environments and perform minimally invasive environmental and biomedical operations. For example, microstructures fabricated in the form of bacterial or eukaryotic flagella can act as artificial microswimmers. Due to limitations in their design and material properties, these simple micromachines lack multifunctionality, effective addressability and manoeuvrability in complex environments. Here we develop an origami-inspired rapid prototyping process for building self-folding, magnetically powered micromachines with complex body plans, reconfigurable shape and controllable motility. Selective reprogramming of the mechanical design and magnetic anisotropy of body parts dynamically modulates the swimming characteristics of the micromachines. We find that tail and body morphologies together determine swimming efficiency and, unlike for rigid swimmers, the choice of magnetic field can subtly change the motility of soft microswimmers.

  19. Soft micromachines with programmable motility and morphology

    NASA Astrophysics Data System (ADS)

    Huang, Hen-Wei; Sakar, Mahmut Selman; Petruska, Andrew J.; Pané, Salvador; Nelson, Bradley J.

    2016-07-01

    Nature provides a wide range of inspiration for building mobile micromachines that can navigate through confined heterogenous environments and perform minimally invasive environmental and biomedical operations. For example, microstructures fabricated in the form of bacterial or eukaryotic flagella can act as artificial microswimmers. Due to limitations in their design and material properties, these simple micromachines lack multifunctionality, effective addressability and manoeuvrability in complex environments. Here we develop an origami-inspired rapid prototyping process for building self-folding, magnetically powered micromachines with complex body plans, reconfigurable shape and controllable motility. Selective reprogramming of the mechanical design and magnetic anisotropy of body parts dynamically modulates the swimming characteristics of the micromachines. We find that tail and body morphologies together determine swimming efficiency and, unlike for rigid swimmers, the choice of magnetic field can subtly change the motility of soft microswimmers.

  20. Optical approaches to the study of foraminiferan motility.

    PubMed

    Travis, J L; Bowser, S S

    1988-01-01

    Microtubules are the major cytoskeletal component of foraminiferan reticulopodia. Video-enhanced differential interference contrast light microscopy has demonstrated that the microtubules serve as the intracellular tracks along which rapid bidirectional organelle transport and cell surface motility occurs. Microtubules appear to move, both axially and laterally within the pseudopodial cytoplasm, and these microtubule translocations appear to drive the various reticulopodial movements. F-actin is localized to discrete filament plaques form at sites of pseudopod-substrate adhesion. Correlative immunofluorescence and electron microscopy reveals a structural interaction between microtubules and the actin-containing filament plaques. Our recent data on reticulopodial motility are discussed in an historical context, and a model for foram motility, based on motile microtubules, is presented.

  1. Elenoside increases intestinal motility

    PubMed Central

    Navarro, E; Alonso, SJ; Navarro, R; Trujillo, J; Jorge, E

    2006-01-01

    AIM: To study the effects of elenoside, an arylnaph-thalene lignan from Justicia hyssopifolia, on gastro-intestinal motility in vivo and in vitro in rats. METHODS: Routine in vivo experimental assessments were catharsis index, water percentage of boluses, intestinal transit, and codeine antagonism. The groups included were vehicle control (propylene glycol-ethanol-plant oil-tween 80), elenoside (i.p. 25 and 50 mg/kg), cisapride (i.p. 10 mg/kg), and codeine phosphate (intragastric route, 50 mg/kg). In vitro approaches used isolated rat intestinal tissues (duodenum, jejunum, and ileum). The effects of elenoside at concentrations of 3.2 x 10-4, 6.4 x 10-4 and 1.2 x 10-3 mol/L, and cisapride at 10-6 mol/L were investigated. RESULTS: Elenoside in vivo produced an increase in the catharsis index and water percentage of boluses and in the percentage of distance traveled by a suspension of activated charcoal. Codeine phosphate antagonized the effect of 25 mg/kg of elenoside. In vitro, elenoside in duodenum, jejunum and ileum produced an initial decrease in the contraction force followed by an increase. Elenoside resulted in decreased intestinal frequency in duodenum, jejunum, and ileum. The in vitro and in vivo effects of elenoside were similar to those produced by cisapride. CONCLUSION: Elenoside is a lignan with an action similar to that of purgative and prokinetics drugs. Elenoside, could be an alternative to cisapride in treatment of gastrointestinal diseases as well as a preventive therapy for the undesirable gastrointestinal effects produced by opioids used for mild to moderate pain. PMID:17131476

  2. Nature and composition of gold-forming fluids at Umm Rus area, Eastern Desert, Egypt: evidence from fluid inclusions in vein materials

    NASA Astrophysics Data System (ADS)

    Harraz, H. Z.; El-Dahhar, M. A.

    1993-04-01

    The Umm Rus gold lode is housed along fractures in granitoid-gabbroic rocks, being largely controlled by a NE-SW trending fracture system that affected the Eastern Desert. Mineralogically, the gold lode consists of quartz and carbonate gangue enclosing minor amounts of auriferous pyrite and arsenopyrite. Trace amounts of sphalerite, galena, marcasite and pyrrhotite are also present. The lode can be divided into: (i) Au-poor, pyrite-quartz vein, (ii) Au-rich, pyrite-arsenopyrite-quartz vein and (iii) gangue dominant. Inspection of primary inclusions from the Umm Rus gold lode showed that the ore was formed from CO 2-H 2O-rich fluids (ca. 30-46 mol % CO 2) of low salinity (6.75-7.75 wt. % NaCl equiv.) and alkaline to neutral pH with a density of 0.76-0.85 g/cc. These data are consistent with dissolution of gold as a bisulphide complex. Deposition of Au most likely occurred over a temperature range of 250-300°C and at pressures around 0.35 Kbars. The deposition may have occurred in response to separation of a liquid CO 2-phase from an originally CO 2-H 2O-rich aqueous fluids. The style of mineralization at Umm Rus bears certain resemblances to Au-bearing quartz veins in the Archaean deposits of Canada and Australia and the "Mother Lode" deposits of the U.S.A.

  3. Characterization of swarming motility in Citrobacter freundii.

    PubMed

    Cong, Yanguang; Wang, Jing; Chen, Zhijin; Xiong, Kun; Xu, Qiwang; Hu, Fuquan

    2011-04-01

    Bacterial swarming motility is a flagella-dependent translocation on the surface environment. It has received extensive attention as a population behavior involving numerous genes. Here, we report that Citrobacter freundii, an opportunistic pathogen, exhibits swarming movement on a solid medium surface with appropriate agar concentration. The swarming behavior of C. freundii was described in detail. Insertional mutagenesis with transposon Mini-Tn5 was carried out to discover genetic determinants related to the swarming of C. freundii. A number of swarming genes were identified, among which flhD, motA, motB, wzx, rfaL, rfaJ, rfbX, rfaG, rcsD, rcsC, gshB, fabF, dam, pgi, and rssB have been characterized previously in other species. In mutants related to lipopolysaccharide synthesis and RcsCDB signal system, a propensity to form poorly motile bacterial aggregates on the agar surface was observed. The aggregates hampered bacterial surface migration. In several mutants, the insertion sites were identified to be in the ORF of yqhC, yeeZ, CKO_03941, glgC, and ttrA, which have never been shown to be involved in swarming. Our results revealed several novel characteristics of swarming motility in C. freundii which are worthy of further study.

  4. Melt inclusion record of CO2 and H2O evolution of magma from Kikai-Akahoya caldera-forming eruption of Satsuma-Iojima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Saito, G.; Morishita, Y.; Kawanabe, Y.

    2009-12-01

    Geological survey and chemical analyses of pyroclastic rocks and melt inclusions in the deposits of Kikai-Akahoya caldera-forming eruption (7.3 ka) of Satsuma-Iojima volcano, Japan, were carried out in order to investigate compositional variation and degassing process οf the magma. Three pyroclastic units were erupted by the eruption successively; Koya-Funakura air-fall pumice (KFA), densely welded Funakura pyroclastic flow deposit and nonwelded Takeshima pyroclastic flow deposit (TPF; Ono et al., 1982). The total mass of the tephra is estimated to be more than 100 km3 (Machida and Arai, 2003). The KFA is a layer of coarse-grained rhyolitic pumice deposit (SiO2=71-72 wt.%) with 2-3m thick. The TPF has a thickness of about 30m and can be divided into at least three units. The deposit mainly consists of rhyolitic pumice (SiO2=70-72 wt.%) and vitric ash with small amount of andesitic scoria (SiO2=58-60 wt.%) and banded pumice. The upper unit is more rich in andesitic scoria than the lower unit. Analyses of major elements and S of the melt inclusions (MIs) in plagioclases and pyroxenes in the pumice and scoria were made by EPMA, and H2O and CO2 by SIMS. Major element composition of MIs in the pumice and scoria is similar to that of groundmass of them, respectively, indicating the melt entrapment just before the eruption. The MIs in the KFA have volatile contents of 4-6 wt.% H2O, <0.007 wt.% CO2 and <0.01 wt.% S. Gas saturation pressure of the magma is calculated to be 100-260 MPa on the basis of the H2O and CO2 contents of the MIs. On the other hand, the MIs in the rhyolitic pumice in the lower TPF have similar H2O and S contents but higher CO2 content (0.01-0.03 wt.%) than those of the KFA. Gas saturation pressure of the magma is calculated to be 130-270 MPa. The MIs in the andesitic scoria in the upper TPF have higher S (0.05-0.12 wt.%), similar CO2 content and lower H2O (2-3 wt.%) contents than those of the lower unit. Gas saturation pressure of the magma is

  5. Esophageal motility disorders: medical therapy.

    PubMed

    Lacy, Brian E; Weiser, Kirsten

    2008-01-01

    Symptoms of chest pain and dysphagia are common in the adult population. Most patients initially undergo an evaluation to exclude anatomic causes (ie, esophagitis, stricture) and cardiovascular disease as the etiology of these symptoms. Patients with persistent symptoms may then be referred for specialized testing of the esophagus, including esophageal manometry. Disorders of esophageal motility, which include achalasia, diffuse esophageal spasm, nutcracker esophagus, hypertensive lower esophageal sphincter, and ineffective motility are often identified in these patients. Unfortunately, the etiology of these disorders has not been well characterized and the treatment has not been standardized. This review will briefly discuss the impact, etiology, and diagnosis of esophageal motility disorders, and then focus on the medical management of these disorders using evidence from well-designed, prospective studies, where available.

  6. Evolution of ore forming fluid in the orogenic type gold deposit in Tavt, Mongolia: trace element geochemistry and fluid inclusions in quartz

    NASA Astrophysics Data System (ADS)

    Lee, K.; Oyungerel, S.; Lee, I.

    2011-12-01

    The Tavt gold deposit of Dzhida-Selengisky metallogenic belt is located in the Dzhida terrane, northern Mongolia. This deposit commonly occurs with massive auriferous quartz veins that contain sulfides and less commonly occurs with disseminated- and stockwork-type quartz veins. Such gold-bearing quartz veins have an average grade of 6.3 g/t Au, 29.4 g/t Ag, and 1.3% Cu. This gold deposit is composed of three stages of quartz vein groups. The first stage quartz group is widely spread with medium to large grain size, showing white-grey and milky white colors. It underwent intensive cataclasis with strong cuts via fractures and includes a small amount of sulfides, secondary minerals and Au. The second stage quartz group is grey and includes an oxidation zone. The oxidation zone distributed on the outside of the vein is brown and green-grey; it is also enriched with sulfide minerals containing gold. This quartz group is located in a brittle and cataclastic zone with the first stage quartz group. The main mineralization process for gold is related to this second stage quartz group. The transition between the first and second groups is not clear, and their contact relationship is complex. The third stage quartz group is transparent to translucent, and has small euhedral crystals that were formed in the second stage quartz group. The third stage of quartz is partly associated with chlorite and montmorillonite that was formed in the latest stage. Each generation of quartz was analyzed by SEM-CL, EPMA, and ICP-MS. Fluid inclusion data were collected from the USGS gas-flow heating/freezing stage and Raman-spectroscopy. The electron microprobe data show the distribution of Al, Ca, K and Fe among distinguished CL intensities and textures of quartz from different stages. The prepared pure quartz samples were analyzed by ICP-MS. The analysis also shows different patterns of trace elements according to the quartz stages.

  7. Preparation, imaging, and quantification of bacterial surface motility assays.

    PubMed

    Morales-Soto, Nydia; Anyan, Morgen E; Mattingly, Anne E; Madukoma, Chinedu S; Harvey, Cameron W; Alber, Mark; Déziel, Eric; Kearns, Daniel B; Shrout, Joshua D

    2015-04-07

    Bacterial surface motility, such as swarming, is commonly examined in the laboratory using plate assays that necessitate specific concentrations of agar and sometimes inclusion of specific nutrients in the growth medium. The preparation of such explicit media and surface growth conditions serves to provide the favorable conditions that allow not just bacterial growth but coordinated motility of bacteria over these surfaces within thin liquid films. Reproducibility of swarm plate and other surface motility plate assays can be a major challenge. Especially for more "temperate swarmers" that exhibit motility only within agar ranges of 0.4%-0.8% (wt/vol), minor changes in protocol or laboratory environment can greatly influence swarm assay results. "Wettability", or water content at the liquid-solid-air interface of these plate assays, is often a key variable to be controlled. An additional challenge in assessing swarming is how to quantify observed differences between any two (or more) experiments. Here we detail a versatile two-phase protocol to prepare and image swarm assays. We include guidelines to circumvent the challenges commonly associated with swarm assay media preparation and quantification of data from these assays. We specifically demonstrate our method using bacteria that express fluorescent or bioluminescent genetic reporters like green fluorescent protein (GFP), luciferase (lux operon), or cellular stains to enable time-lapse optical imaging. We further demonstrate the ability of our method to track competing swarming species in the same experiment.

  8. Motility of Electric Cable Bacteria

    PubMed Central

    Damgaard, Lars Riis; Holm, Simon Agner; Schramm, Andreas; Nielsen, Lars Peter

    2016-01-01

    ABSTRACT Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces with a highly variable speed of 0.5 ± 0.3 μm s−1 (mean ± standard deviation) and time between reversals of 155 ± 108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment. IMPORTANCE This study reports on the motility of cable bacteria, capable of transmitting electrons over centimeter distances. It gives us a new insight into their behavior in sediments and explains previously puzzling findings. Cable bacteria greatly influence their environment, and this article adds significantly to the body of knowledge about this organism. PMID:27084019

  9. Properties of extruded starch-poly(methyl acrylate) graft copolymers prepared from spherulites formed from amylose-oleic acid inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mixtures of high amylose corn starch and oleic acid were processed by steam jet-cooking, and the dispersions were rapidly cooled to yield amylose-oleic acid inclusion complexes as sub-micron spherulites and spherulite aggregates. Dispersions of these spherulite particles were then graft polymerized ...

  10. Theoretical and experimental study of inclusion complexes formed by isoniazid and modified β-cyclodextrins: 1H NMR structural determination and antibacterial activity evaluation.

    PubMed

    Teixeira, Milena G; de Assis, João V; Soares, Cássia G P; Venâncio, Mateus F; Lopes, Juliana F; Nascimento, Clebio S; Anconi, Cleber P A; Carvalho, Guilherme S L; Lourenço, Cristina S; de Almeida, Mauro V; Fernandes, Sergio A; de Almeida, Wagner B

    2014-01-09

    Me-β-cyclodextrin (Me-βCD) and HP-β-cyclodextrin (HP-βCD) inclusion complexes with isoniazid (INH) were prepared with the aim of modulating the physicochemical and biopharmaceutical properties of the guest molecule, a well-known antibuberculosis drug. The architectures of the complexes were initially proposed according to NMR data Job plot and ROESY followed by density functional theory (DFT) calculations of (1)H NMR spectra using the PBE1PBE functional and 6-31G(d,p) basis set, including the water solvent effect with the polarizable continuum model (PCM), for various inclusion modes, providing support for the experimental proposal. An analysis of the (1)H NMR chemical shift values for the isoniazid (H6',8' and H5',9') and cyclodextrins (H3,5) C(1)H hydrogens, which are known to be very adequately described by the DFT methodology, revealed them to be extremely useful, promptly confirming the inclusion complex formation. An included mode which describes Me-βCD partially enclosing the hydrazide group of the INH is predicted as the most favorable supramolecular structure that can be used to explain the physicochemical properties of the encapsulated drug. Antibacterial activity was also evaluated, and the results indicated the inclusion complexes are a potential strategy for tuberculosis treatment.

  11. Melt inclusions: Chapter 6

    USGS Publications Warehouse

    ,; Lowenstern, J. B.

    2014-01-01

    Melt inclusions are small droplets of silicate melt that are trapped in minerals during their growth in a magma. Once formed, they commonly retain much of their initial composition (with some exceptions) unless they are re-opened at some later stage. Melt inclusions thus offer several key advantages over whole rock samples: (i) they record pristine concentrations of volatiles and metals that are usually lost during magma solidification and degassing, (ii) they are snapshots in time whereas whole rocks are the time-integrated end products, thus allowing a more detailed, time-resolved view into magmatic processes (iii) they are largely unaffected by subsolidus alteration. Due to these characteristics, melt inclusions are an ideal tool to study the evolution of mineralized magma systems. This chapter first discusses general aspects of melt inclusions formation and methods for their investigation, before reviewing studies performed on mineralized magma systems.

  12. Motile and non-motile cilia in human pathology: from function to phenotypes.

    PubMed

    Mitchison, Hannah M; Valente, Enza Maria

    2017-01-01

    Ciliopathies are inherited human disorders caused by both motile and non-motile cilia dysfunction that form an important and rapidly expanding disease category. Ciliopathies are complex conditions to diagnose, being multisystem disorders characterized by extensive genetic heterogeneity and clinical variability with high levels of lethality. There is marked phenotypic overlap among distinct ciliopathy syndromes that presents a major challenge for their recognition, diagnosis, and clinical management, in addition to posing an on-going task to develop the most appropriate family counselling. The impact of next-generation sequencing and high-throughput technologies in the last decade has significantly improved our understanding of the biological basis of ciliopathy disorders, enhancing our ability to determine the possible reasons for the extensive overlap in their symptoms and genetic aetiologies. Here, we review the diverse functions of cilia in human health and disease and discuss a growing shift away from the classical clinical definitions of ciliopathy syndromes to a more functional categorization. This approach arises from our improved understanding of this unique organelle, revealed through new genetic and cell biological insights into the discrete functioning of subcompartments of the cilium (basal body, transition zone, intraflagellar transport, motility). Mutations affecting these distinct ciliary protein modules can confer different genetic diseases and new clinical classifications are possible to define, according to the nature and extent of organ involvement. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

  13. TUTORIAL: An introduction to cell motility for the physical scientist

    NASA Astrophysics Data System (ADS)

    Fletcher, Daniel A.; Theriot, Julie A.

    2004-03-01

    Directed, purposeful movement is one of the qualities that we most closely associate with living organisms, and essentially all known forms of life on this planet exhibit some type of self-generated movement or motility. Even organisms that remain sessile most of the time, like flowering plants and trees, are quite busy at the cellular level, with large organelles, including chloroplasts, constantly racing around within cellular boundaries. Directed biological movement requires that the cell be able to convert its abundant stores of chemical energy into mechanical energy. Understanding how this mechanochemical energy transduction takes place and understanding how small biological forces generated at the molecular level are marshaled and organized for large-scale cellular or organismal movements are the focus of the field of cell motility. This tutorial, aimed at readers with a background in physical sciences, surveys the state of current knowledge and recent advances in modeling cell motility.

  14. Axoneme Structure from Motile Cilia.

    PubMed

    Ishikawa, Takashi

    2017-01-03

    The axoneme is the main extracellular part of cilia and flagella in eukaryotes. It consists of a microtubule cytoskeleton, which normally comprises nine doublets. In motile cilia, dynein ATPase motor proteins generate sliding motions between adjacent microtubules, which are integrated into a well-orchestrated beating or rotational motion. In primary cilia, there are a number of sensory proteins functioning on membranes surrounding the axoneme. In both cases, as the study of proteomics has elucidated, hundreds of proteins exist in this compartmentalized biomolecular system. In this article, we review the recent progress of structural studies of the axoneme and its components using electron microscopy and X-ray crystallography, mainly focusing on motile cilia. Structural biology presents snapshots (but not live imaging) of dynamic structural change and gives insights into the force generation mechanism of dynein, ciliary bending mechanism, ciliogenesis, and evolution of the axoneme.

  15. Self-organized cell motility

    NASA Astrophysics Data System (ADS)

    Du, Xinxin; Doubrovinski, Konstantin

    2011-03-01

    Cell migration plays a key role in a wide range of biological phenomena, such as morphogenesis, chemotaxis, and wound healing. Cell locomotion relies on the cytoskeleton, a meshwork of filamentous proteins, intrinsically out of thermodynamic equilibrium and cross-linked by molecular motors, proteins that turn chemical energy into mechanical work. In the course of locomotion, cells remain polarized, i.e. they retain a single direction of motion in the absence of external cues. Traditionally, polarization has been attributed to intracellular signaling. However, recent experiments show that polarization may be a consequence of self-organized cytoskeletal dynamics. Our aim is to elucidate the mechanisms by which persistent unidirectional locomotion may arise through simple mechanical interactions of the cytoskeletal proteins. To this end, we develop a simple physical description of cytoskeletal dynamics. We find that the proposed description accounts for a range of phenomena associated with cell motility, including spontaneous polarization, persistent unidirectional motion, and the co-existence of motile and non-motile states.

  16. Fundoplication improves disordered esophageal motility.

    PubMed

    Heider, T Ryan; Behrns, Kevin E; Koruda, Mark J; Shaheen, Nicholas J; Lucktong, Tananchai A; Bradshaw, Barbara; Farrell, Timothy M

    2003-02-01

    Patients with gastroesophageal reflux disease (GERD) and disordered esophageal motility are at risk for postoperative dysphagia, and are often treated with partial (270-degree) fundoplication as a strategy to minimize postoperative swallowing difficulties. Complete (360-degree) fundoplication, however, may provide more effective and durable reflux protection over time. Recently we reported that postfundoplication dysphagia is uncommon, regardless of preoperative manometric status and type of fundoplication. To determine whether esophageal function improves after fundoplication, we measured postoperative motility in patients in whom disordered esophageal motility had been documented before fundoplication. Forty-eight of 262 patients who underwent laparoscopic fundoplication between 1995 and 2000 satisfied preoperative manometric criteria for disordered esophageal motility (distal esophageal peristaltic amplitude < or =30 mm Hg and/or peristaltic frequency < or =80%). Of these, 19 had preoperative manometric assessment at our facility and consented to repeat study. Fifteen (79%) of these patients had a complete fundoplication and four (21%) had a partial fundoplication. Each patient underwent repeat four-channel esophageal manometry 29.5 +/- 18.4 months (mean +/- SD) after fundoplication. Distal esophageal peristaltic amplitude and peristaltic frequency were compared to preoperative data by paired t test. After fundoplication, mean peristaltic amplitude in the distal esophagus increased by 47% (56.8 +/- 30.9 mm Hg to 83.5 +/- 36.5 mm Hg; P < 0.001) and peristaltic frequency improved by 33% (66.4 +/- 28.7% to 87.6 +/- 16.3%; P < 0.01). Normal esophageal motor function was present in 14 patients (74%) after fundoplication, whereas in five patients the esophageal motor function remained abnormal (2 improved, 1 worsened, and 2 remained unchanged). Three patients with preoperative peristaltic frequencies of 0%, 10%, and 20% improved to 84%, 88%, and 50%, respectively

  17. A relation between a metallic film covering on diamond formed during growth and nanosized inclusions in HPHT as-grown diamond single crystals

    NASA Astrophysics Data System (ADS)

    Yin, L.-W.; Li, M.-S.; Gong, Z.-G.; Bai, Y.-J.; Li, F.-Z.; Hao, Z.-Y.

    One of the most important characteristics and basic phenomena during diamond growth from liquid metal catalyst solutions saturated with carbon at high temperature-high pressure (HPHT) is that there exists a thin metallic film covering on the growing diamond, through which carbon-atom clusters are delivered to the surface of the growing diamond by diffusion. A study of microstructures of such a metallic film and a relation between the thin metallic film and the inclusions trapped in HPHT as-grown diamond single crystals may be helpful to obtain high-purity diamond single crystals. It was found that both the metallic film and the HPHT as-grown diamond single crystals contain some nanostructured regions. Examination by transmission electron microscopy suggests that the microstructure of the thin metallic film is in accordance with nanosized particles contained in HPHT as-grown diamond single crystals. The nanosized particles with several to several tens of nanometers in dimension distribute homogeneously in the metallic film and in the diamond matrix. Generally, the size of the particles in the thin metallic film is relatively larger than that within the diamond matrix. Selected area electron diffraction patterns suggest that the nanosized particles in the metallic film and nanometer inclusions within the diamond are mainly composed of f.c.c. (FeNi)23C6, hexagonal graphite and cubic γ-(FeNi). The formation of the nanosized inclusions within the diamond single crystals is thought not only to relate to the growth process and rapid quenching from high temperature after diamond synthesis, but also to be associated with large amounts of defects in the diamond, because the free energy in these defect areas is very high. The critical size of carbide, γ-(FeNi)and graphite particles within the diamond matrix should decrease and not increase according to thermodynamic theory during quenching from HPHT to room temperature and ambient pressure.

  18. Mechanics model for actin-based motility

    NASA Astrophysics Data System (ADS)

    Lin, Yuan

    2009-02-01

    We present here a mechanics model for the force generation by actin polymerization. The possible adhesions between the actin filaments and the load surface, as well as the nucleation and capping of filament tips, are included in this model on top of the well-known elastic Brownian ratchet formulation. A closed form solution is provided from which the force-velocity relationship, summarizing the mechanics of polymerization, can be drawn. Model predictions on the velocity of moving beads driven by actin polymerization are consistent with experiment observations. This model also seems capable of explaining the enhanced actin-based motility of Listeria monocytogenes and beads by the presence of Vasodilator-stimulated phosphoprotein, as observed in recent experiments.

  19. Mechanics model for actin-based motility.

    PubMed

    Lin, Yuan

    2009-02-01

    We present here a mechanics model for the force generation by actin polymerization. The possible adhesions between the actin filaments and the load surface, as well as the nucleation and capping of filament tips, are included in this model on top of the well-known elastic Brownian ratchet formulation. A closed form solution is provided from which the force-velocity relationship, summarizing the mechanics of polymerization, can be drawn. Model predictions on the velocity of moving beads driven by actin polymerization are consistent with experiment observations. This model also seems capable of explaining the enhanced actin-based motility of Listeria monocytogenes and beads by the presence of Vasodilator-stimulated phosphoprotein, as observed in recent experiments.

  20. Mechanism of Actin-Based Motility

    NASA Astrophysics Data System (ADS)

    Pantaloni, Dominique; Le Clainche, Christophe; Carlier, Marie-France

    2001-05-01

    Spatially controlled polymerization of actin is at the origin of cell motility and is responsible for the formation of cellular protrusions like lamellipodia. The pathogens Listeria monocytogenes and Shigella flexneri, which undergo actin-based propulsion, are acknowledged models of the leading edge of lamellipodia. Actin-based motility of the bacteria or of functionalized microspheres can be reconstituted in vitro from only five pure proteins. Movement results from the regulated site-directed treadmilling of actin filaments, consistent with observations of actin dynamics in living motile cells and with the biochemical properties of the components of the synthetic motility medium.

  1. Bacterial signaling and motility: Sure bets

    SciTech Connect

    Zhulin, Igor B

    2008-01-01

    The IX International Conference on Bacterial Locomotion and Signal Transduction (BLAST IX) was held from 14 to 19 January 2007 in Laughlin, NV, a town in the Mojave Desert on the Nevada-Arizona border near old Route 66 and along the banks of the Colorado River. This area is a home to rattlesnakes, sagebrush, abandoned gold mines, and compulsive gamblers. What better venue could scientists possibly dream of for a professional meeting? So there they were, about 190 scientists gathered in the Aquarius Casino Resort, the largest hotel and casino in Laughlin, discussing the latest advances in the field. Aside from a brief excursion to an abandoned gold mine and a dinner cruise on the Colorado River, the scientists focused on nothing but their data and hypotheses, in spirited arguments and rebuttals, and outlined their visions and future plans in a friendly and open environment. The BLAST IX program was dense, with nearly 50 talks and over 90 posters. For that reason, this meeting report will not attempt to be comprehensive; instead it will first provide general background information on the central topics of the meeting and then highlight only a few talks that were of special interest to us and hopefully to the wider scientific community. We will also attempt to articulate some of the future directions or perspectives to the best of our abilities. The best known and understood bacterial motility mechanism is swimming powered by flagella. The rotation of bacterial flagella drives this form of bacterial movement in an aqueous environment. A bacterial flagellum consists of a helical filament attached to the cell body through a complex structure known as the hook-basal body, which drives flagellar rotation. The essential components of the basal body are the MotA-MotB motor-stator proteins bound to the cytoplasmic membrane. These stator proteins interact with proteins that comprise the supramembrane and cytoplasmic rings, which are components of the motor imbedded in the

  2. Carbonic inclusions

    NASA Astrophysics Data System (ADS)

    Van den Kerkhof, Alfons; Thiéry, Régis

    2001-01-01

    The paper gives an overview of the phase relations in carbonic fluid inclusions with pure, binary and ternary mixtures of the system CO 2-CH 4-N 2, compositions, which are frequently found in geological materials. Phase transitions involving liquid, gas and solid phases in the temperature range between -192°C and 31°C are discussed and presented in phase diagrams ( PT, TX and VX projections). These diagrams can be applied for the interpretation of microthermometry data in order to determine fluid composition and molar volume (or density).

  3. 21 CFR 876.1725 - Gastrointestinal motility monitoring system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gastrointestinal motility monitoring system. 876... Gastrointestinal motility monitoring system. (a) Identification. A gastrointestinal motility monitoring system is a... esophageal motility monitor and tube, the gastrointestinal motility (electrical) system, and...

  4. 21 CFR 876.1725 - Gastrointestinal motility monitoring system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gastrointestinal motility monitoring system. 876... Gastrointestinal motility monitoring system. (a) Identification. A gastrointestinal motility monitoring system is a... esophageal motility monitor and tube, the gastrointestinal motility (electrical) system, and...

  5. 21 CFR 876.1725 - Gastrointestinal motility monitoring system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gastrointestinal motility monitoring system. 876... Gastrointestinal motility monitoring system. (a) Identification. A gastrointestinal motility monitoring system is a... esophageal motility monitor and tube, the gastrointestinal motility (electrical) system, and...

  6. 21 CFR 876.1725 - Gastrointestinal motility monitoring system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gastrointestinal motility monitoring system. 876... Gastrointestinal motility monitoring system. (a) Identification. A gastrointestinal motility monitoring system is a... esophageal motility monitor and tube, the gastrointestinal motility (electrical) system, and...

  7. 21 CFR 876.1725 - Gastrointestinal motility monitoring system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gastrointestinal motility monitoring system. 876... Gastrointestinal motility monitoring system. (a) Identification. A gastrointestinal motility monitoring system is a... esophageal motility monitor and tube, the gastrointestinal motility (electrical) system, and...

  8. Gliding motility in bacteria: insights from studies of Myxococcus xanthus.

    PubMed

    Spormann, A M

    1999-09-01

    Gliding motility is observed in a large variety of phylogenetically unrelated bacteria. Gliding provides a means for microbes to travel in environments with a low water content, such as might be found in biofilms, microbial mats, and soil. Gliding is defined as the movement of a cell on a surface in the direction of the long axis of the cell. Because this definition is operational and not mechanistic, the underlying molecular motor(s) may be quite different in diverse microbes. In fact, studies on the gliding bacterium Myxococcus xanthus suggest that two independent gliding machineries, encoded by two multigene systems, operate in this microorganism. One machinery, which allows individual cells to glide on a surface, independent of whether the cells are moving alone or in groups, requires the function of the genes of the A-motility system. More than 37 A-motility genes are known to be required for this form of movement. Depending on an additional phenotype, these genes are divided into two subclasses, the agl and cgl genes. Videomicroscopic studies on gliding movement, as well as ultrastructural observations of two myxobacteria, suggest that the A-system motor may consist of multiple single motor elements that are arrayed along the entire cell body. Each motor element is proposed to be localized to the periplasmic space and to be anchored to the peptidoglycan layer. The force to glide which may be generated here is coupled to adhesion sites that move freely in the outer membrane. These adhesion sites provide a specific contact with the substratum. Based on single-cell observations, similar models have been proposed to operate in the unrelated gliding bacteria Flavobacterium johnsoniae (formerly Cytophaga johnsonae), Cytophaga strain U67, and Flexibacter polymorphus (a filamentous glider). Although this model has not been verified experimentally, M. xanthus seems to be the ideal organism with which to test it, given the genetic tools available. The second gliding

  9. Gliding Motility in Bacteria: Insights from Studies of Myxococcus xanthus

    PubMed Central

    Spormann, Alfred M.

    1999-01-01

    Gliding motility is observed in a large variety of phylogenetically unrelated bacteria. Gliding provides a means for microbes to travel in environments with a low water content, such as might be found in biofilms, microbial mats, and soil. Gliding is defined as the movement of a cell on a surface in the direction of the long axis of the cell. Because this definition is operational and not mechanistic, the underlying molecular motor(s) may be quite different in diverse microbes. In fact, studies on the gliding bacterium Myxococcus xanthus suggest that two independent gliding machineries, encoded by two multigene systems, operate in this microorganism. One machinery, which allows individual cells to glide on a surface, independent of whether the cells are moving alone or in groups, requires the function of the genes of the A-motility system. More than 37 A-motility genes are known to be required for this form of movement. Depending on an additional phenotype, these genes are divided into two subclasses, the agl and cgl genes. Videomicroscopic studies on gliding movement, as well as ultrastructural observations of two myxobacteria, suggest that the A-system motor may consist of multiple single motor elements that are arrayed along the entire cell body. Each motor element is proposed to be localized to the periplasmic space and to be anchored to the peptidoglycan layer. The force to glide which may be generated here is coupled to adhesion sites that move freely in the outer membrane. These adhesion sites provide a specific contact with the substratum. Based on single-cell observations, similar models have been proposed to operate in the unrelated gliding bacteria Flavobacterium johnsoniae (formerly Cytophaga johnsonae), Cytophaga strain U67, and Flexibacter polymorphus (a filamentous glider). Although this model has not been verified experimentally, M. xanthus seems to be the ideal organism with which to test it, given the genetic tools available. The second gliding

  10. Quantification of Cell Edge Velocities and Traction Forces Reveals Distinct Motility Modules during Cell Spreading

    PubMed Central

    Cai, Yunfei; Xenias, Harry; Spielman, Ingrid; Shneidman, Anna V.; David, Lawrence A.; Döbereiner, Hans-Günther; Wiggins, Chris H.; Sheetz, Michael P.

    2008-01-01

    Actin-based cell motility and force generation are central to immune response, tissue development, and cancer metastasis, and understanding actin cytoskeleton regulation is a major goal of cell biologists. Cell spreading is a commonly used model system for motility experiments – spreading fibroblasts exhibit stereotypic, spatially-isotropic edge dynamics during a reproducible sequence of functional phases: 1) During early spreading, cells form initial contacts with the surface. 2) The middle spreading phase exhibits rapidly increasing attachment area. 3) Late spreading is characterized by periodic contractions and stable adhesions formation. While differences in cytoskeletal regulation between phases are known, a global analysis of the spatial and temporal coordination of motility and force generation is missing. Implementing improved algorithms for analyzing edge dynamics over the entire cell periphery, we observed that a single domain of homogeneous cytoskeletal dynamics dominated each of the three phases of spreading. These domains exhibited a unique combination of biophysical and biochemical parameters – a motility module. Biophysical characterization of the motility modules revealed that the early phase was dominated by periodic, rapid membrane blebbing; the middle phase exhibited continuous protrusion with very low traction force generation; and the late phase was characterized by global periodic contractions and high force generation. Biochemically, each motility module exhibited a different distribution of the actin-related protein VASP, while inhibition of actin polymerization revealed different dependencies on barbed-end polymerization. In addition, our whole-cell analysis revealed that many cells exhibited heterogeneous combinations of motility modules in neighboring regions of the cell edge. Together, these observations support a model of motility in which regions of the cell edge exhibit one of a limited number of motility modules that, together

  11. Active gel model of amoeboid cell motility

    NASA Astrophysics Data System (ADS)

    Callan-Jones, A. C.; Voituriez, R.

    2013-02-01

    We develop a model of amoeboid cell motility based on active gel theory. Modeling the motile apparatus of a eukaryotic cell as a confined layer of finite length of poroelastic active gel permeated by a solvent, we first show that, due to active stress and gel turnover, an initially static and homogeneous layer can undergo a contractile-type instability to a polarized moving state in which the rear is enriched in gel polymer. This agrees qualitatively with motile cells containing an actomyosin-rich uropod at their rear. We find that the gel layer settles into a steadily moving, inhomogeneous state at long times, sustained by a balance between contractility and filament turnover. In addition, our model predicts an optimal value of the gel-substrate adhesion leading to maximum layer speed, in agreement with cell motility assays. The model may be relevant to motility of cells translocating in complex, confining environments that can be mimicked experimentally by cell migration through microchannels.

  12. Sperm motility under conditions of weightlessness.

    PubMed

    Engelmann, U; Krassnigg, F; Schill, W B

    1992-01-01

    The aim of this study was to determine the differences in motility of frozen and thawed bull spermatozoa under conditions of weightlessness compared with ground conditions. The tests were performed within a series of scientific and technologic experiments under microgravity using sounding rockets in the Technologische Experimente unter Schwerelosigkeit (TEXUS) program launched in Kiruna, North Sweden. Using a computerized sperm motility analyzer, significant differences were found in sperm motility under microgravity compared with sperm under gravitational conditions on earth. Computer analysis showed alterations in straight line and curvilinear velocity, as well as in linearity values. The amount of progressively motile spermatozoa, including all spermatozoa with a velocity > 20 microns/second, increased significantly from 24% +/- 9.5% in the reference test to 49% +/- 7.6% in the microgravity test. In conclusion, there is strong evidence that gravity influences sperm motility.

  13. Accurate quantitation for in vitro refolding of single domain antibody fragments expressed as inclusion bodies by referring the concomitant expression of a soluble form in the periplasms of Escherichia coli.

    PubMed

    Noguchi, Tomoaki; Nishida, Yuichi; Takizawa, Keiji; Cui, Yue; Tsutsumi, Koki; Hamada, Takashi; Nishi, Yoshisuke

    2017-03-01

    Single domain antibody fragments from two species, a camel VHH (PM1) and a shark VNAR (A6), were derived from inclusion bodies of E. coli and refolded in vitro following three refolding recipes for comparing refolding efficiencies: three-step cold dialysis refolding (TCDR), one-step hot dialysis refolding (OHDR), and one-step cold dialysis refolding (OCDR), as these fragments were expressed as 'a soluble form' either in cytoplasm or periplasm, but the amount were much less than those expressed as 'an insoluble form (inclusion body)' in cytoplasm and periplasm. In order to verify the refolding efficiencies from inclusion bodies correctly, proteins purified from periplasmic soluble fractions were used as reference samples. These samples showed far-UV spectra of a typical β-sheet-dominant structure in circular dichroism (CD) spectroscopy and so did the refolded samples as well. As the maximal magnitude of ellipticity in millidegrees (θmax) observed at a given wave length was proportional to the concentrations of the respective reference samples, we could draw linear regression lines for the magnitudes vs. sample concentrations. By using these lines, we measured the concentrations for the refolded PM1 and A6 samples purified from solubilized cytoplasmic insoluble fractions. The refolding efficiency of PM1 was almost 50% following TCDR and 40% and 30% following OHDR and OCDR, respectively, whereas the value of A6 was around 30% following TCDR, and out of bound for quantitation following the other two recipes. The ELISA curves, which were derived from the refolded samples, coincided better with those obtained from the reference samples after converting the values from the protein-concentrations at recovery to the ones of refolded proteins using recovery ratios, indicating that such a correction gives better results for the accurate measure of the ELISA curves than those without correction. Our method require constructing a dual expression system, expressed both in

  14. The Actin Filament-Binding Protein Coronin Regulates Motility in Plasmodium Sporozoites

    PubMed Central

    Bane, Kartik S.; Singer, Mirko; Reinig, Miriam; Klug, Dennis; Heiss, Kirsten; Baum, Jake; Mueller, Ann-Kristin; Frischknecht, Friedrich

    2016-01-01

    Parasites causing malaria need to migrate in order to penetrate tissue barriers and enter host cells. Here we show that the actin filament-binding protein coronin regulates gliding motility in Plasmodium berghei sporozoites, the highly motile forms of a rodent malaria-causing parasite transmitted by mosquitoes. Parasites lacking coronin show motility defects that impair colonization of the mosquito salivary glands but not migration in the skin, yet result in decreased transmission efficiency. In non-motile sporozoites low calcium concentrations mediate actin-independent coronin localization to the periphery. Engagement of extracellular ligands triggers an intracellular calcium release followed by the actin-dependent relocalization of coronin to the rear and initiation of motility. Mutational analysis and imaging suggest that coronin organizes actin filaments for productive motility. Using coronin-mCherry as a marker for the presence of actin filaments we found that protein kinase A contributes to actin filament disassembly. We finally speculate that calcium and cAMP-mediated signaling regulate a switch from rapid parasite motility to host cell invasion by differentially influencing actin dynamics. PMID:27409081

  15. Modulation of mammalian sperm motility by quercetin.

    PubMed

    Nass-Arden, L; Breitbart, H

    1990-04-01

    The flavonoid quercetin inhibits collective motility of ejaculated ram spermatozoa in the first 2 hr of incubation; during the next 3-4 hr motility is stimulated. To explain this interesting effect, we followed the influence of quercetin on sperm glycolysis, extracellular pH, ATP content, mitochondrial respiration, and lipid peroxidation. The collective motility of untreated cells is decreased to about 40% of the original motility during two hours of incubation. During this time, the rate of glycolysis is constant, respiration rate is increasing, there is no change in ATP content, the rate of lipid peroxidation is very slow, and the extracellular pH became very acidic (pH 5.5). It is concluded that motility is decreased due to this acidification. This acidification is prevented to some extent by quercetin, which indirectly inhibits glycolysis. Quercetin inhibits motility due to the inhibition of the plasma membrane calcium pump, as we showed previously (Breitbart et al., J Biol Chem 260:11548-11553, 1985). The motility of untreated cells is arrested after 3.5 hr of incubation, whereas quercetin-treated cells show high motility, which continues for additional 2-3 hr. After 3.5 hr, the control cells show no glycolytic activity, ATP content and respiration rates are decreased, and rate of lipid peroxidation is highly increased. At this time, quercetin-treated cells show no glycolytic activity, only a small decrease in ATP content and respiratory rate, and a very low rate of lipid peroxidation. Based on these data it is concluded that sperm motility after 3.5 hr of incubation is dependent mainly on mitochondrial respiration.(ABSTRACT TRUNCATED AT 250 WORDS)

  16. Genetic Analysis of Collective Motility of Paenibacillus sp. NAIST15-1

    PubMed Central

    Kobayashi, Kazuo; Kanesaki, Yu

    2016-01-01

    Bacteria have developed various motility mechanisms to adapt to a variety of solid surfaces. A rhizosphere isolate, Paenibacillus sp. NAIST15-1, exhibited unusual motility behavior. When spotted onto 1.5% agar media, Paenibacillus sp. formed many colonies, each of which moved around actively at a speed of 3.6 μm/sec. As their density increased, each moving colony began to spiral, finally forming a static round colony. Despite its unusual motility behavior, draft genome sequencing revealed that both the composition and organization of flagellar genes in Paenibacillus sp. were very similar to those in Bacillus subtilis. Disruption of flagellar genes and flagellar stator operons resulted in loss of motility. Paenibacillus sp. showed increased transcription of flagellar genes and hyperflagellation on hard agar media. Thus, increased flagella and their rotation drive Paenibacillus sp. motility. We also identified a large extracellular protein, CmoA, which is conserved only in several Paenibacillus and related species. A cmoA mutant could neither form moving colonies nor move on hard agar media; however, motility was restored by exogenous CmoA. CmoA was located around cells and enveloped cell clusters. Comparison of cellular behavior between the wild type and cmoA mutant indicated that extracellular CmoA is involved in drawing water out of agar media and/or smoothing the cell surface interface. This function of CmoA probably enables Paenibacillus sp. to move on hard agar media. PMID:27764113

  17. Motility precedes egress of malaria parasites from oocysts

    PubMed Central

    Klug, Dennis; Frischknecht, Friedrich

    2017-01-01

    Malaria is transmitted when an infected Anopheles mosquito deposits Plasmodium sporozoites in the skin during a bite. Sporozoites are formed within oocysts at the mosquito midgut wall and are released into the hemolymph, from where they invade the salivary glands and are subsequently transmitted to the vertebrate host. We found that a thrombospondin-repeat containing sporozoite-specific protein named thrombospondin-releated protein 1 (TRP1) is important for oocyst egress and salivary gland invasion, and hence for the transmission of malaria. We imaged the release of sporozoites from oocysts in situ, which was preceded by active motility. Parasites lacking TRP1 failed to migrate within oocysts and did not egress, suggesting that TRP1 is a vital component of the events that precede intra-oocyst motility and subsequently sporozoite egress and salivary gland invasion. DOI: http://dx.doi.org/10.7554/eLife.19157.001 PMID:28115054

  18. Estimation of the glass forming ability of the Fe-based bulk metallic glass Fe68.8C7.0Si3.5B5.0P9.6Cr2.1Mo2.0Al2.0 that contains non-metallic inclusions

    NASA Astrophysics Data System (ADS)

    Li, Hongxiang; Lu, Zhaoping; Yi, Seonghoon

    2009-02-01

    For the mass production of bulk metallic glasses, the use of industrial raw materials that contain certain amounts of inclusions is inevitable. The glass-forming ability of bulk metallic glasses, i.e., the critical cooling rate for glass formation upon solidification, is closely related to the nature of heterogeneous nucleation offered by inclusions during the solidification process. Significantly different effects of various types of inclusions on the glass forming ability of the alloy Fe68.8C7.0Si3.5B5.0P9.6Cr2.1Mo2.0Al2.0 are demonstrated in this study. The origins of the effects of different inclusions on the glass forming ability are analyzed through thermodynamic, crystallographic and classical heterogeneous nucleation kinetic theories.

  19. Regulation of Eukaryotic Flagellar Motility

    NASA Astrophysics Data System (ADS)

    Mitchell, David R.

    2005-03-01

    The central apparatus is essential for normal eukaryotic flagellar bend propagation as evidenced by the paralysis associated with mutations that prevent central pair (CP) assembly. Interactions between doublet-associated radial spokes and CP projections are thought to modulate spoke-regulated protein kinases and phosphatases on outer doublets, and these enzymes in turn modulate dynein activity. To better understand CP control mechanisms, we determined the three-dimensional structure of the Chlamydomonas reinhardtii CP complex and analyzed CP orientation during formation and propagation of flagellar bending waves. We show that a single CP microtubule, C1, is near the outermost doublet in curved regions of the flagellum, and this orientation is maintained by twists between successive principal and reverse bends. The Chlamydomonas CP is inherently twisted; twists are not induced by bend formation, and do not depend on forces or signals transmitted through spoke-central pair interactions. We hypothesize that CP orientation passively responds to bend formation, and that bend propagation drives rotation of the CP and maintains a constant CP orientation in bends, which in turn permits signal transduction between specific CP projections and specific doublet-associated dyneins through radial spokes. The central pair kinesin, Klp1, although essential for normal motility, is therefore not the motor that drives CP rotation. The CP also acts as a scaffold for enzymes that maintain normal intraflagellar ATP concentration.

  20. Deterministic patterns in cell motility

    NASA Astrophysics Data System (ADS)

    Lavi, Ido; Piel, Matthieu; Lennon-Duménil, Ana-Maria; Voituriez, Raphaël; Gov, Nir S.

    2016-12-01

    Cell migration paths are generally described as random walks, associated with both intrinsic and extrinsic noise. However, complex cell locomotion is not merely related to such fluctuations, but is often determined by the underlying machinery. Cell motility is driven mechanically by actin and myosin, two molecular components that generate contractile forces. Other cell functions make use of the same components and, therefore, will compete with the migratory apparatus. Here, we propose a physical model of such a competitive system, namely dendritic cells whose antigen capture function and migratory ability are coupled by myosin II. The model predicts that this coupling gives rise to a dynamic instability, whereby cells switch from persistent migration to unidirectional self-oscillation, through a Hopf bifurcation. Cells can then switch to periodic polarity reversals through a homoclinic bifurcation. These predicted dynamic regimes are characterized by robust features that we identify through in vitro trajectories of dendritic cells over long timescales and distances. We expect that competition for limited resources in other migrating cell types can lead to similar deterministic migration modes.

  1. Numerical Evaluation of Efficacy of Glutamate on Gastrointestinal Motility: Rapid MRI Study.

    PubMed

    Nakayama, Shinsuke; Teramoto, Hidemi

    2016-01-01

     The umami taste amino acid, glutamate acts as a signaling molecule in multiple cellular systems in the body, including the brain and gastrointestinal tract. Therefore, glutamate may affect appetite by modulating gastrointestinal motility as well as through taste perception. In this study, we examined the effect of glutamate on gastric emptying and duodenal motility, by using rapid magnetic resonance imaging (MRI). Ten healthy male volunteers participated in the measurements. Abdominal coronal MR images were successively acquired after ingestion of a liquid meal with and without monosodium L-glutamate (MSG). Image analysis was performed with a homemade segment software, in which respiratory motions were cancelled automatically by minimizing an energy function, thereby allowing participants breathe freely during MRI measurements. In two out of 10 participants, gastric emptying slowed down, while in the remaining eight participants, gastric residual volume decreased to 84% without MSG, and to 73% with MSG after 60 min. The inclusion of MSG enhanced duodenal motility, judging from changes in, 1) the magnitude of the duodenal area, 2) the center of gravity, and 3) the mean velocity of the wall motions. The third parameter most significantly indicated the excitatory effect of MSG on duodenum motility (3-7 fold increase). In conclusion, the present observations of rapid MRI indicate that MSG accelerates gastric emptying by facilitating duodenal motility, at least in healthy subjects with positive responses to MSG. This suggests the possible use of MSG as a prokinetic nutrient for improving the quality of life in hospitalized patients after a clinical assessment.

  2. Mammalian Sperm Motility: Observation and Theory

    NASA Astrophysics Data System (ADS)

    Gaffney, E. A.; Gadêlha, H.; Smith, D. J.; Blake, J. R.; Kirkman-Brown, J. C.

    2011-01-01

    Mammalian spermatozoa motility is a subject of growing importance because of rising human infertility and the possibility of improving animal breeding. We highlight opportunities for fluid and continuum dynamics to provide novel insights concerning the mechanics of these specialized cells, especially during their remarkable journey to the egg. The biological structure of the motile sperm appendage, the flagellum, is described and placed in the context of the mechanics underlying the migration of mammalian sperm through the numerous environments of the female reproductive tract. This process demands certain specific changes to flagellar movement and motility for which further mechanical insight would be valuable, although this requires improved modeling capabilities, particularly to increase our understanding of sperm progression in vivo. We summarize current theoretical studies, highlighting the synergistic combination of imaging and theory in exploring sperm motility, and discuss the challenges for future observational and theoretical studies in understanding the underlying mechanics.

  3. Select Acetophenones Modulate Flagellar Motility in Chlamydomonas

    PubMed Central

    Evans, Shakila K.; Pearce, Austin A.; Ibezim, Prudence K.; Primm, Todd P.; Gaillard, Anne R.

    2009-01-01

    Acetophenones were screened for activity against positive phototaxis of Chlamydomonas cells, a process that requires coordinated flagellar motility. The structure-activity relationships of a series of acetophenones are reported, including acetophenones that affect flagellar motility and cell viability. Notably, 4-methoxyacetophenone, 3,4-dimethoxyacetophenone, and 4-hydroxyacetophenone induced negative phototaxis in Chlamydomonas, suggesting interference with activity of flagellar proteins and control of flagellar dominance. PMID:20659114

  4. Invisible gold distribution on pyrite and ore-forming fluid process of the Huangshan orogenic-type gold deposit of Zhejiang, SE China: implications from mineralogy, trace elements, impurity and fluid inclusion studies

    NASA Astrophysics Data System (ADS)

    Sundarrajan, Vijay Anand; Li, Zilong; Hu, Yizhou; Fu, Xuheng; Zhu, Yuhuo

    2016-07-01

    The Huangshan orogenic-type gold deposit in Zhejiang of SE China occurred in quartz-pyrite veins. It is hosted by phyllonite that underwent greenschist-facies metamorphism along a large Jiangshan-Shaoxing tectonic belt with a NE-SW direction. Trace elemental characteristics, ore-forming process and invisible gold on different forms of pyrite and quartz are studied. The Au associated pyrite can be classified into two categories; recrystallized pyrite and euhedral pyrite. The precipitation of invisible Au on pyrite is mainly derived by Co and Ni with AuHS2 - complex in the mineralizing fluids in different events. The XPS results revealed that valence states of Au3+ replaced 2Fe2+ in the pyrite and Au0 replaced Si4+ in the quartz structure. The electron paramagnetic resonance and trace elemental results suggested that the element pairs of Ge-Li-Al in quartz and Mn-Co-Ni in pyrite have distinct impurities as identified. A fluid inclusion study showed that the auriferous quartz is characterized by low-saline and CO2-rich fluids. Coexistence of the type I-type III inclusions and same range of homogenization temperature with different mode are evidences of immiscible fluid process. The temperature-pressure values of ca. 250 °C/1250 bar and ca. 220 °C/780 bar for gold precipitation have been calculated by intersection of coexisting fluids during the entrapment. The Huangshan orogenic-type gold deposit may be associated with the Wuyi-Yunkai orogeny during the early Paleozoic, including an upper-mid greenschist-facies metamorphism (450-420 Ma). All the features suggest that the Huangshan gold deposit is probably a product linking with the early Paleozoic orogeny in South China.

  5. Cross-regulation of Pseudomonas motility systems: the intimate relationship between flagella, pili and virulence.

    PubMed

    Kazmierczak, Barbara I; Schniederberend, Maren; Jain, Ruchi

    2015-12-01

    Pseudomonas aeruginosa navigates using two distinct forms of motility, swimming and twitching. A polar flagellum and Type 4 pili power these movements, respectively, allowing P. aeruginosa to attach to and colonize surfaces. Single cell imaging and particle tracking algorithms have revealed a wide range of bacterial surface behaviors which are regulated by second messengers cyclic-di-GMP and cAMP; the production of these signals is, in turn, responsive to the engagement of motility organelles with a surface. Innate immune defense systems, long known to recognize structural components of flagella, appear to respond to motility itself. The association of motility with both upregulation of virulence and induction of host defense mechanisms underlies the complex contributions of flagella and pili to P. aeruginosa pathogenesis.

  6. Study of the inclusion complexes formed between cetirizine and α-, β-, and γ-cyclodextrin and evaluation on their taste-masking properties.

    PubMed

    Stojanov, Mladen; Wimmer, Reinhard; Larsen, Kim L

    2011-08-01

    Complexation properties of cetirizine dihydrochloride (cetirizine) with α-, β-, and γ-cyclodextrin (CD) were investigated by ultra violet (UV) and nuclear magnetic resonance (NMR) spectroscopies and isothermal titration calorimetry (ITC). The use of the continuous variation method, applied on UV and NMR data, demonstrated 1:1 complex stoichiometry for cetirizine-α-CD, cetirizine-β-CD, and cetirizine-γ-CD, respectively. NMR two-dimensional Rotational nuclear Overhauser Effect SpectroscopY experiments revealed that for α- and β-CD, the complexation takes place by including either the phenyl or chlorophenyl ring of the cetirizine into the CD cavity, whereas in the case of γ-CD, both rings can be included simultaneously. Association constants (K(a)) determined by UV spectroscopy demonstrated that cetirizine forms more stable complex with β-CD (K(a) = 5641 ± 358 M(-1)) than α-CD (K(a) = 1434 ± 60 M(-1)). No information could be extracted from the UV spectroscopic analysis of cetirizine-γ-CD solutions. ITC results for association constant determination were in compliance with UV results and confirmed that the highest association constant was found for the cetirizine-β-CD complex (2540 ± 122 M(-1)). The association constants from ITC measurements for cetirizine-γ-CD and cetirizine-α-CD complexes were found to be 1200 ± 50 and 800 ± 22 M(-1) , respectively. Taste-masking studies revealed that β-CD is the only native CD recommendable for oral pharmaceutical formulations.

  7. Toward the reconstitution of synthetic cell motility

    PubMed Central

    Siton-Mendelson, Orit; Bernheim-Groswasser, Anne

    2016-01-01

    ABSTRACT Cellular motility is a fundamental process essential for embryonic development, wound healing, immune responses, and tissues development. Cells are mostly moving by crawling on external, or inside, substrates which can differ in their surface composition, geometry, and dimensionality. Cells can adopt different migration phenotypes, e.g., bleb-based and protrusion-based, depending on myosin contractility, surface adhesion, and cell confinement. In the few past decades, research on cell motility has focused on uncovering the major molecular players and their order of events. Despite major progresses, our ability to infer on the collective behavior from the molecular properties remains a major challenge, especially because cell migration integrates numerous chemical and mechanical processes that are coupled via feedbacks that span over large range of time and length scales. For this reason, reconstituted model systems were developed. These systems allow for full control of the molecular constituents and various system parameters, thereby providing insight into their individual roles and functions. In this review we describe the various reconstituted model systems that were developed in the past decades. Because of the multiple steps involved in cell motility and the complexity of the overall process, most of the model systems focus on very specific aspects of the individual steps of cell motility. Here we describe the main advancement in cell motility reconstitution and discuss the main challenges toward the realization of a synthetic motile cell. PMID:27019160

  8. Tumor invasion as dysregulated cell motility.

    PubMed

    Kassis, J; Lauffenburger, D A; Turner, T; Wells, A

    2001-04-01

    Investigations across a range of disciplines over the past decade have brought the study of cell motility and its role in invasion to an exciting threshold. The biophysical forces proximally involved in generating cell locomotion, as well as the underlying signaling and genomic regulatory processes, are gradually becoming elucidated. We now appreciate the intricacies of the many cellular and extracellular events that modulate cell migration. This has enabled the demonstration of a causal role of cell motility in tumor progression, with various points of 'dysregulation' of motility being responsible for promoting invasion. In this paper, we describe key fundamental principles governing cell motility and branch out to describe the essence of the data that describe these principles. It has become evident that many proposed models may indeed be converging into a tightly-woven tapestry of coordinated events which employ various growth factors and their receptors, adhesion receptors (integrins), downstream molecules, cytoskeletal components, and altered genomic regulation to accomplish cell motility. Tumor invasion occurs in response to dysregulation of many of these modulatory points; specific examples include increased signaling from the EGF receptor and through PLC gamma, altered localization and expression of integrins, changes in actin modifying proteins and increased transcription from specific promoter sites. This diversity of alterations all leading to tumor invasion point to the difficulty of correcting causal events leading to tumor invasion and rather suggest that the underlying common processes required for motility be targeted for therapeutic intervention.

  9. Flagellar motility in eukaryotic human parasites.

    PubMed

    Krüger, Timothy; Engstler, Markus

    2015-10-01

    A huge variety of protists rely on one or more motile flagella to either move themselves or move fluids and substances around them. Many of these flagellates have evolved a symbiotic or parasitic lifestyle. Several of the parasites have adapted to human hosts, and include agents of prevalent and serious diseases. These unicellular parasites have become specialised in colonising a wide range of biological niches within humans. They usually have diverse transmission cycles, and frequently manifest a variety of distinct morphological stages. The motility of the single or multiple flagella plays important but understudied roles in parasite transmission, host invasion, dispersal, survival, proliferation and pathology. In this review we provide an overview of the important human pathogens that possess a motile flagellum for at least part of their life cycle. We highlight recently published studies that aim to elucidate motility mechanisms, and their relevance for human disease. We then bring the physics of swimming at the microscale into context, emphasising the importance of interdisciplinary approaches for a full understanding of flagellate motility - especially in light of the parasites' microenvironments and population dynamics. Finally, we summarise some important technological aspects, describing challenges for the field and possibilities for motility analyses in the future.

  10. Inclusion and Museums: Developing Inclusive Practice

    ERIC Educational Resources Information Center

    Shepherd, Hannah

    2009-01-01

    Recent policy on inclusion has had an impact on the development of museum galleries and related educational provision. Museums are used as learning organisations and, as such, need to consider how to create an inclusive environment. However, inclusive provision for people with learning difficulties in museums tends to be isolated and small scale,…

  11. Memo mediates ErbB2-driven cell motility.

    PubMed

    Marone, Romina; Hess, Daniel; Dankort, David; Muller, William J; Hynes, Nancy E; Badache, Ali

    2004-06-01

    Clinical studies have revealed that cancer patients whose tumours have increased ErbB2 expression tend to have more aggressive, metastatic disease, which is associated with parameters predicting a poor outcome. The molecular basis underlying ErbB2-dependent cell motility and metastases formation, however, still remains poorly understood. In this study, we show that activation of a set of signalling molecules, including MAPK, phosphatidylinositol-3-OH kinase (PI(3)K) and Src, is required for Neu/ErbB2-dependent lamellipodia formation and for motility of breast carcinoma cells. Stimulation of these molecules, however, failed to induce efficient cell migration in the absence of Neu/ErbB2 phosphorylation at Tyr 1201 or Tyr 1227. We describe a novel molecule, Memo (mediator of ErbB2-driven cell motility), that interacts with a phospho-Tyr 1227-containing peptide, most probably through the Shc adaptor protein. After Neu/ErbB2 activation, Memo-defective cells form actin fibres and grow lamellipodia, but fail to extend microtubules towards the cell cortex. Our data suggest that Memo controls cell migration by relaying extracellular chemotactic signals to the microtubule cytoskeleton.

  12. Exopolysaccharides promote Myxococcus xanthus social motility by inhibiting cellular reversals.

    PubMed

    Zhou, Tianyi; Nan, Beiyan

    2017-02-01

    The biofilm-forming bacterium Myxococcus xanthus moves on surfaces as structured swarms utilizing type IV pili-dependent social (S) motility. In contrast to isolated cells that reverse their moving direction frequently, individual cells within swarms rarely reverse. The regulatory mechanisms that inhibit cellular reversal and promote the formation of swarms are not well understood. Here we show that exopolysaccharides (EPS), the major extracellular components of M. xanthus swarms, inhibit cellular reversal in a concentration-dependent manner. Thus, individual wild-type cells reverse less frequently in swarms due to high local EPS concentrations. In contrast, cells defective in EPS production hyper-reverse their moving direction and show severe defects in S-motility. Surprisingly, S-motility and wild-type reversal frequency are restored in double mutants that are defective in both EPS production and the Frz chemosensory system, indicating that EPS regulates cellular reversal in parallel to the Frz pathway. Here we clarify that besides functioning as the structural scaffold in biofilms, EPS is a self-produced signal that coordinates the group motion of the social bacterium M. xanthus.

  13. Statistical physical models of cellular motility

    NASA Astrophysics Data System (ADS)

    Banigan, Edward J.

    Cellular motility is required for a wide range of biological behaviors and functions, and the topic poses a number of interesting physical questions. In this work, we construct and analyze models of various aspects of cellular motility using tools and ideas from statistical physics. We begin with a Brownian dynamics model for actin-polymerization-driven motility, which is responsible for cell crawling and "rocketing" motility of pathogens. Within this model, we explore the robustness of self-diffusiophoresis, which is a general mechanism of motility. Using this mechanism, an object such as a cell catalyzes a reaction that generates a steady-state concentration gradient that propels the object in a particular direction. We then apply these ideas to a model for depolymerization-driven motility during bacterial chromosome segregation. We find that depolymerization and protein-protein binding interactions alone are sufficient to robustly pull a chromosome, even against large loads. Next, we investigate how forces and kinetics interact during eukaryotic mitosis with a many-microtubule model. Microtubules exert forces on chromosomes, but since individual microtubules grow and shrink in a force-dependent way, these forces lead to bistable collective microtubule dynamics, which provides a mechanism for chromosome oscillations and microtubule-based tension sensing. Finally, we explore kinematic aspects of cell motility in the context of the immune system. We develop quantitative methods for analyzing cell migration statistics collected during imaging experiments. We find that during chronic infection in the brain, T cells run and pause stochastically, following the statistics of a generalized Levy walk. These statistics may contribute to immune function by mimicking an evolutionarily conserved efficient search strategy. Additionally, we find that naive T cells migrating in lymph nodes also obey non-Gaussian statistics. Altogether, our work demonstrates how physical

  14. Ultrastructural cytochemical analysis of intranuclear arsenic inclusions

    SciTech Connect

    Sorensen, E.M.B.

    1987-01-01

    To establish the chemical composition of the arsenic inclusion, freshly isolated preparations of inclusions and epon-embedded thin sections of inclusions were subjected to ultrastructural cytochemical analysis. Intranuclear inclusions are composed of amorphous, arsenic-containing subunits aligned linearly to form a coiled complex. Lipase, ribonuclease, deoxyribonuclease, trypsin, pepsin, protease, amylase, or ethylenediaminetetraacetic acid (EDTA) was used to digest or chelate these inclusions. Following enzymatic digestion or chelation, the electron opacity of inclusions was compared with that of control sections exposed for equal times to equivalent solutions lacking the enzymes. Exposure to amylase caused a consistent reduction in the electron opacity of thin sections of inclusions and almost complete digestion of the freshly isolated preparations of inclusions. This was indicative of the presence of a carbohydrate moiety within arsenic inclusions. Incubation of inclusions with EDTA resulted in solubilization of freshly isolated and thin-sectioned embedded material. These data indicated that the intranuclear arsenic inclusion is composed of both metallic and carbohydrate moieties, confirming earlier studies which identified arsenic within inclusions using instrumental neutron activation analysis and x-ray microprobe analysis.

  15. Fourier analysis of cell motility: correlation of motility with metastatic potential.

    PubMed Central

    Partin, A W; Schoeniger, J S; Mohler, J L; Coffey, D S

    1989-01-01

    We report the development of a computerized, mathematical system for quantitating the various types of cell motility. This Fourier analysis method simultaneously quantifies for individual cells (i) temporal changes in cell shape represented by cell ruffling, undulation, and pseudopodal extension, (ii) cell translation, and (iii) average cell size and shape. This spatial-temporal Fourier analysis was tested on a series of well-characterized animal tumor cell lines of rat prostatic cancer to study in a quantitative manner the correlation of cell motility with increasing in vivo metastatic potential. Fourier motility coefficients measuring pseudopodal extension correlated best with metastatic potential in the cell lines studied. This study demonstrated that Fourier analysis provides quantitative measurement of cell motility that may be applied to the study of biological processes. This analysis should aid in the study of the motility of individual cells in various areas of cellular and tumor biology. Images PMID:2919174

  16. Motility modes of the parasite Trypanosoma brucei

    NASA Astrophysics Data System (ADS)

    Temel, Fatma Zeynep; Qu, Zijie; McAllaster, Michael; de Graffenried, Christopher; Breuer, Kenneth

    2015-11-01

    The parasitic single-celled protozoan Trypanosoma brucei causes African Sleeping Sickness, which is a fatal disease in humans and animals that threatens more than 60 million people in 36 African countries. Cell motility plays a critical role in the developmental phases and dissemination of the parasite. Unlike many other motile cells such as bacteria Escherichia coli or Caulobacter crescentus, the flagellum of T. brucei is attached along the length of its awl-like body, producing a unique mode of motility that is not fully understood or characterized. Here, we report on the motility of T. brucei, which swims using its single flagellum employing both rotating and undulating propulsion modes. We tracked cells in real-time in three dimensions using fluorescent microscopy. Data obtained from experiments using both short-term tracking within the field of view and long-term tracking using a tracking microscope were analyzed. Motility modes and swimming speed were analyzed as functions of cell size, rotation rate and undulation pattern. Research supported by NSF.

  17. Study of human sperm motility post cryopreservation

    PubMed Central

    Oberoi, Bhavni; Kumar, Sushil; Talwar, Pankaj

    2014-01-01

    Background Cryopreservation of spermatozoa is a widely used technique to preserve the fertility of males. It can also benefit the armed forces personnel who are to be sent for long recruitments, while leaving their families behind. This study, apart from studying the effects of freezing and thawing, reveals the effect of the post thaw interval on the motility of the human spermatozoa and thus widens the insemination window period. Methods A detailed semen analysis was carried out as per the WHO guidelines for 25 samples. The samples were then washed, analysed and frozen in liquid nitrogen. The semen samples were subsequently thawed and similarly analysed after 20 min and 40 min of thawing. This was then followed by statistical analysis of the comparative motilities. Results Motility of sperms is found to decrease after cryopreservation. However, the study revealed that after thawing a significant increase in the motility of the sperms was noted with the progression of time (p < 0.05). Conclusion By simulating conditions similar to the in vivo conditions for the post thaw semen samples, we can safely wait, confirm the parameters like motility and count, and then inseminate the samples instead of blindly inseminating them immediately after thawing. PMID:25382909

  18. A Novel Inducer of Roseobacter Motility Is Also a Disruptor of Algal Symbiosis

    PubMed Central

    Sule, Preeti

    2013-01-01

    Silicibacter sp. strain TM1040, a member of the Roseobacter clade, forms a symbiosis with unicellular phytoplankton, which is inextricably linked to the biphasic “swim or stick” lifestyle of the bacteria. Mutations in flaC bias the population toward the motile phase. Renewed examination of the FlaC− strain (HG1016) uncovered that it is composed of two different cells: a pigmented type, PS01, and a nonpigmented cell, PS02, each of which has an identical mutation in flaC. While monocultures of PS01 and PS02 had few motile cells (0.6 and 6%, respectively), coculturing the two strains resulted in a 10-fold increase in the number of motile cells. Cell-free supernatants from coculture or wild-type cells were fully capable of restoring motility to PS01 and PS02, which was due to increased fliC3 (flagellin) transcription, FliC3 protein levels per cell, and flagella synthesis. The motility-inducing compound has an estimated mass of 226 Da, as determined by mass spectrometry, and is referred to as Roseobacter Motility Inducer (RMI). Mutations affecting genes involved in phenyl acetic acid synthesis significantly reduced RMI, while defects in tropodithietic acid (TDA) synthesis had marginal or no effect on RMI. RMI biosynthesis is induced by p-coumaric acid, a product of algal lignin degradation. When added to algal cultures, RMI caused loss of motility, cell enlargement, and vacuolization in the algal cells. RMI is a new member of the roseobacticide family of troponoid compounds whose activities affect roseobacters, by shifting their population toward motility, as well as their phytoplankton hosts, through an algicidal effect. PMID:23161030

  19. Inclusive Education in Taiwan

    ERIC Educational Resources Information Center

    Wu-Tien, Wu

    2007-01-01

    As an echo of the worldwide movement of inclusive education and because of the conviction of inclusive ideas, special education in Taiwan is moving toward a goal of inclusion, though not necessarily full inclusion. While its terminology is as yet undesignated, principles and strategies are significantly reflected in the Special Education Act and…

  20. Limits to Inclusion

    ERIC Educational Resources Information Center

    Hansen, Janne Hedegaard

    2012-01-01

    In this article, I will argue that a theoretical identification of the limit to inclusion is needed in the conceptual identification of inclusion. On the one hand, inclusion is formulated as a vision that is, in principle, limitless. On the other hand, there seems to be an agreement that inclusion has a limit in the pedagogical practice. However,…

  1. Microgravity, bacteria, and the influence of motility

    NASA Astrophysics Data System (ADS)

    Benoit, Michael R.; Klaus, David M.

    Space microbiology studies date back to the 1960s, with most investigations reporting that increased bacterial populations occur in flight compared to ground controls. Several exceptions to these findings, however, have created controversy and complicated explanations of how, or whether, microgravity affects microorganisms. Upon closer examination of the literature, we identified a trend relating cell motility to experimental outcome. Related studies conducted in microgravity analog devices, such as the clinostat or rotating wall vessel bioreactor, further corroborate this trend. We review the literature regarding bacterial growth experiments conducted in space (and using microgravity analogs) and analyze the influence of bacterial motility.

  2. Response of a Motile/Non-Motile Escherichia coli Front to Hydrodynamic excitations

    NASA Astrophysics Data System (ADS)

    Baabour, Magali; Douarche, Carine; Salin, Dominique

    2014-11-01

    In a recent study (Douarche et al. PRL 102, 198101 (2009)), it has been shown that the motility of Escherichia coli (E. coli) is highly correlated to the oxygen level in a minimal medium: bacteria swim as long as they are provided with oxygen but reversibly transit to a non-motile state when they lack of it. Hence, when oxygen diffuses into an anaerobic sample of non-motile bacteria, a propagating front delineates a region of motile bacteria where oxygen is present from a region of non-motile ones where the oxygen is still not present. To study the response of this front to hydrodynamics excitation, we use the same fluorescent E. coli bacterial solution in rectangular cross section glass cells open to air (oxygen) at one inlet. After bacteria have consumed the oxygen of the solution, the presence of the oxygen only at the open edge of the sample leads to the formation of an analogous stationary front between motile and non-motile bacteria. We follow the response of this front to hydrodynamics flows such as an oscillating Poiseuille flow or natural convection. We analyze both the macroscopic behavior (shape and width) of the front as well as the microscopic displacements of individual bacteria. The dispersive behavior of this bacterial front is compared to the one of equivalent. Collaboration between Laboratories FAST and LPS, Univ Paris Sud and CNRS.

  3. Extending the molecular clutch beyond actin-based cell motility

    NASA Astrophysics Data System (ADS)

    Havrylenko, Svitlana; Mezanges, Xavier; Batchelder, Ellen; Plastino, Julie

    2014-10-01

    Many cell movements occur via polymerization of the actin cytoskeleton beneath the plasma membrane at the front of the cell, forming a protrusion called a lamellipodium, while myosin contraction squeezes forward the back of the cell. In what is known as the ‘molecular clutch’ description of cell motility, forward movement results from the engagement of the acto-myosin motor with cell-matrix adhesions, thus transmitting force to the substrate and producing movement. However during cell translocation, clutch engagement is not perfect, and as a result, the cytoskeleton slips with respect to the substrate, undergoing backward (retrograde) flow in the direction of the cell body. Retrograde flow is therefore inversely proportional to cell speed and depends on adhesion and acto-myosin dynamics. Here we asked whether the molecular clutch was a general mechanism by measuring motility and retrograde flow for the Caenorhabditis elegans sperm cell in different adhesive conditions. These cells move by adhering to the substrate and emitting a dynamic lamellipodium, but the sperm cell does not contain an acto-myosin cytoskeleton. Instead the lamellipodium is formed by the assembly of major sperm protein, which has no biochemical or structural similarity to actin. We find that these cells display the same molecular clutch characteristics as acto-myosin containing cells. We further show that retrograde flow is produced both by cytoskeletal assembly and contractility in these cells. Overall this study shows that the molecular clutch hypothesis of how polymerization is transduced into motility via adhesions is a general description of cell movement regardless of the composition of the cytoskeleton.

  4. Extending the molecular clutch beyond actin-based cell motility

    PubMed Central

    Havrylenko, Svitlana; Mezanges, Xavier; Batchelder, Ellen; Plastino, Julie

    2014-01-01

    Many cell movements occur via polymerization of the actin cytoskeleton beneath the plasma membrane at the front of the cell, forming a protrusion called a lamellipodium, while myosin contraction squeezes forward the back of the cell. In what is known as the “molecular clutch” description of cell motility, forward movement results from the engagement of the acto-myosin motor with cell-matrix adhesions, thus transmitting force to the substrate and producing movement. However during cell translocation, clutch engagement is not perfect, and as a result, the cytoskeleton slips with respect to the substrate, undergoing backward (retrograde) flow in the direction of the cell body. Retrograde flow is therefore inversely proportional to cell speed and depends on adhesion and acto-myosin dynamics. Here we asked whether the molecular clutch was a general mechanism by measuring motility and retrograde flow for the Caenorhabditis elegans sperm cell in different adhesive conditions. These cells move by adhering to the substrate and emitting a dynamic lamellipodium, but the sperm cell does not contain an acto-myosin cytoskeleton. Instead the lamellipodium is formed by the assembly of Major Sperm Protein (MSP), which has no biochemical or structural similarity to actin. We find that these cells display the same molecular clutch characteristics as acto-myosin containing cells. We further show that retrograde flow is produced both by cytoskeletal assembly and contractility in these cells. Overall this study shows that the molecular clutch hypothesis of how polymerization is transduced into motility via adhesions is a general description of cell movement regardless of the composition of the cytoskeleton. PMID:25383039

  5. Towards Inclusion: An Australian Perspective

    ERIC Educational Resources Information Center

    Forbes, Fiona

    2007-01-01

    This article outlines the views of the Australian Special Education Principals' Association (ASEPA) on inclusion and the impact this is having on Australian Government Schools from a school based perspective. ASEPA is a relatively young association and was formed in 1997 out of the need to put forward the case to support students with special…

  6. The effects of temperature and motility on the advective transport of a deep subsurface bacteria through saturated sediment

    SciTech Connect

    McCaulou, Douglas Ray

    1993-01-01

    Replicate column experiments were done to quantify the effects of temperature and bacterial motility on advective transport through repacked, but otherwise unaltered, natural aquifer sediment. The bacteria used in this study, A0500, was a flagellated, spore-forming rod isolated from the deep subsurface at DOE`s Savannah River Laboratory. Motility was controlled by turning on flagellar metabolism at 18°C but off at 40°α), estimated using a steady-state filtration model. The observed greater microsphere removal at the higher temperature agreed with the physical-chemical model, but bacteria removal at 18{degrees}C was only half that at 4°C. The sticking efficiency for non-motile A0500 (4°C) was over three times that of the motile A0500 (18°C), 0.073 versus 0.022 respectively. Analysis of complete breakthrough curves using a non-steady, kinetically limited, transport model to estimate the time scales of attachment and detachment suggested that motile A 0500 bacteria traveled twice as far as non-motile A 0500 bacteria before becoming attached. Once attached, non-motile colloids detached on the time scale of 9 to 17 days. The time scale for detachment of motile A0500 bacteria was shorter, 4 to 5 days. Results indicate that bacterial attachment was reversible and detachment was enhanced by bacterial motifity. The kinetic energy of bacterial motility changed the attachment-detachment kinetics in favor of the detached state. The chemical factors responsible for the enhanced transport are not known. However, motility may have caused weakly held bacteria to detach from the secondary minimum, and possibly from the primary minimum, as described by DLVO theory.

  7. Semiautomated Motility Assay For Determining Toxicity

    NASA Technical Reports Server (NTRS)

    Noever, David A.; Cronise, Raymond

    1996-01-01

    Improved method of assessing toxicities of various substances based on observation of effects of those substances on motilities of manageably small number of cells of protozoan species Tetrahema pyriformis. Provides repeatable, standardized tests with minimal handling by technicians and with minimal exposure of technicians to chemicals. Rapid and economical alternative to Draize test.

  8. Methods for fabricating microarrays of motile bacteria.

    PubMed

    Rozhok, Sergey; Shen, Clifton K-F; Littler, Pey-Lih H; Fan, Zhifang; Liu, Chang; Mirkin, Chad A; Holz, Richard C

    2005-04-01

    Motile bacterial cell microarrays were fabricated by attaching Escherichia coli K-12 cells onto predesigned 16-mercaptohexadecanoic acid patterned microarrays, which were covalently functionalized with E. coli antibodies or poly-L-lysine. By utilizing 11-mercaptoundecyl-penta(ethylene glycol) or 11-mercapto-1-undecanol as passivating molecules, nonspecific binding of E. coli was significantly reduced. Microcontact printing and dip-pen nanolithography were used to prepare microarrays for bacterial adhesion, which was studied by optical fluorescence and atomic force microscopy. These data indicate that single motile E. coli can be attached to predesigned line or dot features and binding can occur via the cell body or the flagella of bacteria. Adherent bacteria are viable (remain alive and motile after adhesion to patterned surface features) for more than four hours. Individual motile bacterial cells can be placed onto predesigned surface features that are at least 1.3 microm in diameter or larger. The importance of controlling the adhesion of single bacterial cell to a surface is discussed with regard to biomotor design.

  9. Esophageal motility disorders after gastric banding.

    PubMed

    O'Rourke, R W; Deveney, C W; McConnell, D B; Wolfe, B M; Jobe, B A

    2007-01-01

    The long-term effects of gastric banding on esophageal function are not well described. This report describes a 28-year-old woman who developed signs and symptoms of abnormal esophageal motility and lower esophageal sphincter hypotension after gastric banding for morbid obesity. The current literature addressing the effects of gastric banding on esophageal function in light of this case report is discussed.

  10. Esophageal motility abnormalities in gastroesophageal reflux disease.

    PubMed

    Martinucci, Irene; de Bortoli, Nicola; Giacchino, Maria; Bodini, Giorgia; Marabotto, Elisa; Marchi, Santino; Savarino, Vincenzo; Savarino, Edoardo

    2014-05-06

    Esophageal motility abnormalities are among the main factors implicated in the pathogenesis of gastroesophageal reflux disease. The recent introduction in clinical and research practice of novel esophageal testing has markedly improved our understanding of the mechanisms contributing to the development of gastroesophageal reflux disease, allowing a better management of patients with this disorder. In this context, the present article intends to provide an overview of the current literature about esophageal motility dysfunctions in patients with gastroesophageal reflux disease. Esophageal manometry, by recording intraluminal pressure, represents the gold standard to diagnose esophageal motility abnormalities. In particular, using novel techniques, such as high resolution manometry with or without concurrent intraluminal impedance monitoring, transient lower esophageal sphincter (LES) relaxations, hypotensive LES, ineffective esophageal peristalsis and bolus transit abnormalities have been better defined and strongly implicated in gastroesophageal reflux disease development. Overall, recent findings suggest that esophageal motility abnormalities are increasingly prevalent with increasing severity of reflux disease, from non-erosive reflux disease to erosive reflux disease and Barrett's esophagus. Characterizing esophageal dysmotility among different subgroups of patients with reflux disease may represent a fundamental approach to properly diagnose these patients and, thus, to set up the best therapeutic management. Currently, surgery represents the only reliable way to restore the esophagogastric junction integrity and to reduce transient LES relaxations that are considered to be the predominant mechanism by which gastric contents can enter the esophagus. On that ground, more in depth future studies assessing the pathogenetic role of dysmotility in patients with reflux disease are warranted.

  11. [Increased spontaneous uterine motility with serotonin].

    PubMed

    Lechner, W; Sölder, E; Sölder, B; Kölle, D; Huter, O

    1992-01-01

    The influence of serotonine, a vasoactive neurotransmitter, on the spontaneous motility of uterine strips was investigated. A highly significant (p less than 0.001) increase of uterine activity was observed when serotonine 10(-6) M was added to the perfusing medium.

  12. Irish Mathematics Teachers' Attitudes towards Inclusion

    ERIC Educational Resources Information Center

    Whitty, Elaine; Clarke, Marie

    2012-01-01

    This paper through the theoretical framework of constructive attitude theory explores mathematics teachers' attitudes and pedagogical strategies with reference to inclusive practice. The authors argue that though teachers may have formed positive inclusive attitudes, the translation of these into practice does not always occur and poses…

  13. Inclusive Schooling Policy: An Educational Detective Story?

    ERIC Educational Resources Information Center

    Moss, Julianne

    2003-01-01

    Since the publication of the Salamanca statement (UNESCO 1994), inclusive schooling has formed a growing part of the deliberations of the special education community. Inclusive schooling research in Australia in the main continues to reproduce traditions of the special education field, emphasising the dominant psychological perspectives that have…

  14. Fluid Inclusion Gas Analysis

    DOE Data Explorer

    Dilley, Lorie

    2013-01-01

    Fluid inclusion gas analysis for wells in various geothermal areas. Analyses used in developing fluid inclusion stratigraphy for wells and defining fluids across the geothermal fields. Each sample has mass spectrum counts for 180 chemical species.

  15. Shock Re-equilibration of Fluid Inclusions

    NASA Technical Reports Server (NTRS)

    Madden, M. E. Elwood; Horz, F.; Bodnar, R. J.

    2004-01-01

    Fluid inclusions (microscopic volumes of fluid trapped within minerals as they precipitate) are extremely common in terrestrial minerals formed under a wide range of geological conditions from surface evaporite deposits to kimberlite pipes. While fluid inclusions in terrestrial rocks are nearly ubiquitous, only a few fluid inclusion-bearing meteorites have been documented. The scarcity of fluid inclusions in meteoritic materials may be a result of (a) the absence of fluids when the mineral was formed on the meteorite parent body or (b) the destruction of fluid inclusions originally contained in meteoritic materials by subsequent shock metamorphism. However, the effects of impact events on pre-existing fluid inclusions trapped in target and projectile rocks has received little study. Fluid inclusions trapped prior to the shock event may be altered (re-equilibrated) or destroyed due to the high pressures, temperatures, and strain rates associated with impact events. By examining the effects of shock deformation on fluid inclusion properties and textures we may be able to better constrain the pressure-temperature path experienced by terrestrial and meteoritic shocked materials and also gain a clearer understanding of why fluid inclusions are rarely found in meteorite samples.

  16. The enigma of eugregarine epicytic folds: where gliding motility originates?

    PubMed Central

    2013-01-01

    Background In the past decades, many studies focused on the cell motility of apicomplexan invasive stages as they represent a potential target for chemotherapeutic intervention. Gregarines (Conoidasida, Gregarinasina) are a heterogeneous group that parasitize invertebrates and urochordates, and are thought to be an early branching lineage of Apicomplexa. As characteristic of apicomplexan zoites, gregarines are covered by a complicated pellicle, consisting of the plasma membrane and the closely apposed inner membrane complex, which is associated with a number of cytoskeletal elements. The cell cortex of eugregarines, the epicyte, is more complicated than that of other apicomplexans, as it forms various superficial structures. Results The epicyte of the eugregarines, Gregarina cuneata, G. polymorpha and G. steini, analysed in the present study is organised in longitudinal folds covering the entire cell. In mature trophozoites and gamonts, each epicytic fold exhibits similar ectoplasmic structures and is built up from the plasma membrane, inner membrane complex, 12-nm filaments, rippled dense structures and basal lamina. In addition, rib-like myonemes and an ectoplasmic network are frequently observed. Under experimental conditions, eugregarines showed varied speeds and paths of simple linear gliding. In all three species, actin and myosin were associated with the pellicle, and this actomyosin complex appeared to be restricted to the lateral parts of the epicytic folds. Treatment of living gamonts with jasplakinolide and cytochalasin D confirmed that actin actively participates in gregarine gliding. Contributions to gliding of specific subcellular components are discussed. Conclusions Cell motility in gregarines and other apicomplexans share features in common, i.e. a three-layered pellicle, an actomyosin complex, and the polymerisation of actin during gliding. Although the general architecture and supramolecular organisation of the pellicle is not correlated with

  17. Creating an Inclusive School.

    ERIC Educational Resources Information Center

    Villa, Richard A., Ed.; Thousand, Jacqueline S., Ed.

    This collection of readings in support of inclusive education for students with disabilities offers rationales for inclusion, personal accounts of individuals involved, and strategies for facilitating change. Stressed throughout is the idea that inclusion is an attitude or belief system, not an action or set of actions. The readings identify…

  18. Inclusion in Middle Tennessee

    ERIC Educational Resources Information Center

    Salter, Derrick; Ashley, Mandi; Hayes, Brandalyn

    2013-01-01

    The overall purpose of this study was to provide school districts within Tennessee with more research about how weekly hours of inclusion impact student achievement. Specifically, researchers examined which models of inclusion were in use in two school districts in Tennessee, administrators' and teachers' perceptions of inclusion, and whether or…

  19. Footstep towards Inclusive Education

    ERIC Educational Resources Information Center

    Abbas, Faiza; Zafar, Aneeka; Naz, Tayyaba

    2016-01-01

    Inclusive education is a rising trend in the world. The first step towards inclusive education is providing the awareness to the general education teachers. This study focused to investigate the general education teachers of primary and secondary level awareness about the special education and inclusive education. This study is descriptive method…

  20. Towards Inclusive Schooling

    ERIC Educational Resources Information Center

    Gafoor, K. Abdul

    2010-01-01

    Social inclusion is the process that will enable every person in society to participate in normal activities of societies they live in, including education, employment, public services and social recreational activities. For the development of an inclusive society, preparation of younger generation also needs to be inclusive. Our schools must…

  1. Inclusive Education in Bangladesh

    ERIC Educational Resources Information Center

    Ahsan, Mohammad Tariq; Burnip, Lindsay

    2007-01-01

    This article reports on inclusive education in Bangladesh for children with special needs. Bangladesh is not behind other developed countries in enacting laws and declarations in favour of inclusive education, but a lack of resources is the main barrier in implementing inclusive education. Special education and integrated education models exist in…

  2. Evolutionarily divergent, unstable filamentous actin is essential for gliding motility in apicomplexan parasites.

    PubMed

    Skillman, Kristen M; Diraviyam, Karthikeyan; Khan, Asis; Tang, Keliang; Sept, David; Sibley, L David

    2011-10-01

    Apicomplexan parasites rely on a novel form of actin-based motility called gliding, which depends on parasite actin polymerization, to migrate through their hosts and invade cells. However, parasite actins are divergent both in sequence and function and only form short, unstable filaments in contrast to the stability of conventional actin filaments. The molecular basis for parasite actin filament instability and its relationship to gliding motility remain unresolved. We demonstrate that recombinant Toxoplasma (TgACTI) and Plasmodium (PfACTI and PfACTII) actins polymerized into very short filaments in vitro but were induced to form long, stable filaments by addition of equimolar levels of phalloidin. Parasite actins contain a conserved phalloidin-binding site as determined by molecular modeling and computational docking, yet vary in several residues that are predicted to impact filament stability. In particular, two residues were identified that form intermolecular contacts between different protomers in conventional actin filaments and these residues showed non-conservative differences in apicomplexan parasites. Substitution of divergent residues found in TgACTI with those from mammalian actin resulted in formation of longer, more stable filaments in vitro. Expression of these stabilized actins in T. gondii increased sensitivity to the actin-stabilizing compound jasplakinolide and disrupted normal gliding motility in the absence of treatment. These results identify the molecular basis for short, dynamic filaments in apicomplexan parasites and demonstrate that inherent instability of parasite actin filaments is a critical adaptation for gliding motility.

  3. Evolutionarily Divergent, Unstable Filamentous Actin Is Essential for Gliding Motility in Apicomplexan Parasites

    PubMed Central

    Skillman, Kristen M.; Diraviyam, Karthikeyan; Khan, Asis; Tang, Keliang; Sept, David; Sibley, L. David

    2011-01-01

    Apicomplexan parasites rely on a novel form of actin-based motility called gliding, which depends on parasite actin polymerization, to migrate through their hosts and invade cells. However, parasite actins are divergent both in sequence and function and only form short, unstable filaments in contrast to the stability of conventional actin filaments. The molecular basis for parasite actin filament instability and its relationship to gliding motility remain unresolved. We demonstrate that recombinant Toxoplasma (TgACTI) and Plasmodium (PfACTI and PfACTII) actins polymerized into very short filaments in vitro but were induced to form long, stable filaments by addition of equimolar levels of phalloidin. Parasite actins contain a conserved phalloidin-binding site as determined by molecular modeling and computational docking, yet vary in several residues that are predicted to impact filament stability. In particular, two residues were identified that form intermolecular contacts between different protomers in conventional actin filaments and these residues showed non-conservative differences in apicomplexan parasites. Substitution of divergent residues found in TgACTI with those from mammalian actin resulted in formation of longer, more stable filaments in vitro. Expression of these stabilized actins in T. gondii increased sensitivity to the actin-stabilizing compound jasplakinolide and disrupted normal gliding motility in the absence of treatment. These results identify the molecular basis for short, dynamic filaments in apicomplexan parasites and demonstrate that inherent instability of parasite actin filaments is a critical adaptation for gliding motility. PMID:21998582

  4. Esophageal motility disorders in HIV patients.

    PubMed

    Zalar, Alberto E; Olmos, Martín A; Piskorz, Eduardo L; Magnanini, Fernando L

    2003-05-01

    Opportunistic esophageal infections (Candida, cytomegalovirus, herpes simplex virus) and idiophatic esophageal ulcerations are commonly found in HIV patients. However, motility disorders of the esophagus have seldom been investigated in this population. The aim of this prospective study was to determine the presence of motility disorders in HIV patients with esophageal symptoms (with or without associated lesions detected by endoscopy) and in HIV patients without esophageal symptoms and normal esophagoscopy. Eigthteen consecutive HIV patients (10 male, 8 female, ages 20-44 years, mean age 33.5; 8 HIV positive and 10 AIDS) were studied prospectively. Nine patients complained of esophageal symptoms, e.g, dysphagia/odynophagia (group 1) and 9 had symptoms not related to esophageal disease, such as diarrhea, abdominal pain, or gastrointestinal bleeding (group 2). All patients underwent upper endoscopy; mucosal biopsies were taken when macroscopic esophageal lesions were identified or when the patients were symptomatic even if the esophageal mucosa was normal. Esophageal manometry was performed in the 18 patients, using a 4-channel water-perfused system according to a standardized technique. Sixteen of the 18 patients (88.8%) had baseline manometric abnormalities. In group 1, 8/9 patients had esophageal motility disorders: nutcrackeresophagus in 1, hypertensive lower esophageal sphincter (LES) with incomplete relaxation in 2, nonspecific esophageal motility disorders (NEMD) in 3, diffuse esophageal spasm in 1, esophageal hypocontraction with low LES pressure in 1. Six of these 9 patients had lesions detected by endoscopy: CMV ulcers in 2, idiopathic ulcers in 1, candidiasis in 1, idiopathic ulcer + candidiasis in 1, nonspecific esophagitis in 1; and 3/9 had normal endoscopy and normal esophageal biopsies. In group 2, 8/9 patients had abnormal motility: hypertensive LES with incomplete relaxation in 1, nutcracker esophagus in 2, esophageal hypocontraction in 3, and NEMD

  5. [Motility and functional gastrointestinal disorders].

    PubMed

    Mearin, Fermín; Rey, Enrique; Balboa, Agustín

    2014-09-01

    This article discusses the studies on functional and motor gastrointestinal disorders presented at the 2014 Digestive Diseases Week conference that are of greatest interest to us. New data have been provided on the clinical importance of functional gastrointestinal disorders, with recent prevalence data for irritable bowel syndrome and fecal incontinence. We know more about the pathophysiological mechanisms of the various functional disorders, especially irritable bowel syndrome, which has had the largest number of studies. Thus, we have gained new data on microinflammation, genetics, microbiota, psychological aspects, etc. Symptoms such as abdominal distension have gained interest in the scientific community, both in terms of patients with irritable bowel syndrome and those with constipation. From the diagnostic point of view, the search continues for a biomarker for functional gastrointestinal disorders, especially for irritable bowel syndrome. In the therapeutic area, the importance of diet for these patients (FODMAP, fructans, etc.) is once again confirmed, and data is provided that backs the efficacy of already marketed drugs such as linaclotide, which rule out the use of other drugs such as mesalazine for patients with irritable bowel syndrome. This year, new forms of drug administration have been presented, including metoclopramide nasal sprays and granisetron transdermal patches for patients with gastroparesis. Lastly, a curiosity that caught our attention was the use of a vibrating capsule to stimulate gastrointestinal transit in patients with constipation.

  6. A cell number-counting factor regulates the cytoskeleton and cell motility in Dictyostelium

    PubMed Central

    Tang, Lei; Gao, Tong; McCollum, Catherine; Jang, Wonhee; Vicker, Michael G.; Ammann, Robin R.; Gomer, Richard H.

    2002-01-01

    Little is known about how a morphogenetic rearrangement of a tissue is affected by individual cells. Starving Dictyostelium discoideum cells aggregate to form dendritic streams, which then break up into groups of ≈2 × 104 cells. Cell number is sensed at this developmental stage by using counting factor (CF), a secreted complex of polypeptides. A high extracellular concentration of CF indicates that there is a large number of cells, which then causes the aggregation stream to break up. Computer simulations indicated that stream breakup could be caused by CF decreasing cell–cell adhesion and/or increasing cell motility, and we observed that CF does indeed decrease cell–cell adhesion. We find here that CF increases cell motility. In Dictyostelium, motility is mediated by actin and myosin. CF increases the amounts of polymerized actin and the ABP-120 actin-crosslinking protein. Partially inhibiting motility by using drugs that interfere with actin polymerization reduces stream dissipation, resulting in fewer stream breaks and thus larger groups. CF also potentiates the phosphorylation and redistribution of myosin while repressing its basal level of assembly. The computer simulations indicated that a narrower distribution of group sizes results when a secreted factor modulates both adhesion and motility. CF thus seems to induce the morphogenesis of streams into evenly sized groups by increasing actin polymerization, ABP-120 levels, and myosin phosphorylation and decreasing adhesion and myosin polymerization. PMID:11818526

  7. A cell number-counting factor regulates the cytoskeleton and cell motility in Dictyostelium.

    PubMed

    Tang, Lei; Gao, Tong; McCollum, Catherine; Jang, Wonhee; Vicker, Michael G; Ammann, Robin R; Gomer, Richard H

    2002-02-05

    Little is known about how a morphogenetic rearrangement of a tissue is affected by individual cells. Starving Dictyostelium discoideum cells aggregate to form dendritic streams, which then break up into groups of approximately 2 x 10(4) cells. Cell number is sensed at this developmental stage by using counting factor (CF), a secreted complex of polypeptides. A high extracellular concentration of CF indicates that there is a large number of cells, which then causes the aggregation stream to break up. Computer simulations indicated that stream breakup could be caused by CF decreasing cell-cell adhesion and/or increasing cell motility, and we observed that CF does indeed decrease cell-cell adhesion. We find here that CF increases cell motility. In Dictyostelium, motility is mediated by actin and myosin. CF increases the amounts of polymerized actin and the ABP-120 actin-crosslinking protein. Partially inhibiting motility by using drugs that interfere with actin polymerization reduces stream dissipation, resulting in fewer stream breaks and thus larger groups. CF also potentiates the phosphorylation and redistribution of myosin while repressing its basal level of assembly. The computer simulations indicated that a narrower distribution of group sizes results when a secreted factor modulates both adhesion and motility. CF thus seems to induce the morphogenesis of streams into evenly sized groups by increasing actin polymerization, ABP-120 levels, and myosin phosphorylation and decreasing adhesion and myosin polymerization.

  8. Immunohistochemical expression of Type IV Collagen and Autocrine Motility Factor Receptor in Odontogenic Tumours

    PubMed Central

    Sethi, Sneha

    2014-01-01

    Background: Autocrine motility factor receptor (AMFR) is a tumour motility stimulating protein secreted by tumour cells. The protein encoded by this gene is a glycosylated transmembrane protein and a receptor for autocrine motility factor. It has been known to play a role in progression of neoplastic lesions. Basement membranes are specialized extracellular matrices that serve as structural barriers as well as substrates for cellular interactions. The network of type IV collagen is thought to define the scaffold integrating other components such as laminins and perlecan into highly organized supramolecular architecture. The aim of this study was to determine and evaluate the immunohistochemical expression of Type IV Collagen and Autocrine motility factor receptor in odontogenic lesions. Materials and Methods: Immunohistochemical expression of Type IV Collagen and Autocrine motility factor receptor was evaluated in 31 odontogenic lesions, including unicystic ameloblastoma, multicystic ameloblastoma, keratocystic odontogenic tumour and ameloblastic carcinoma. Normal follicular tissue formed the control. Results: Maximum expression for Type IV Collagen was seen in multicystic ameloblastoma and minimum expression in keratocystic odontogenic tumour. The maximum expression of AMFR was seen in ameloblastic carcinoma and minimum expression in multicystic ameloblastoma. Conclusion: The results of this study suggested an association of loss of expression of type IV Collagen with progression of lesion. AMFR expression was found to be associated with the aggressive potential of tumours. PMID:25478440

  9. Bacterial spread from cell to cell: beyond actin-based motility.

    PubMed

    Kuehl, Carole J; Dragoi, Ana-Maria; Talman, Arthur; Agaisse, Hervé

    2015-09-01

    Several intracellular pathogens display the ability to propagate within host tissues by displaying actin-based motility in the cytosol of infected cells. As motile bacteria reach cell-cell contacts they form plasma membrane protrusions that project into adjacent cells and resolve into vacuoles from which the pathogen escapes, thereby achieving spread from cell to cell. Seminal studies have defined the bacterial and cellular factors that support actin-based motility. By contrast, the mechanisms supporting the formation of protrusions and their resolution into vacuoles have remained elusive. Here, we review recent advances in the field showing that Listeria monocytogenes and Shigella flexneri have evolved pathogen-specific mechanisms of bacterial spread from cell to cell.

  10. Experimental and Mathematical-Modeling Characterization of Trypanosoma cruzi Epimastigote Motility

    PubMed Central

    Arias-del-Angel, Jorge A.; Dévora-Canales, Diego; Manning-Cela, Rebeca G.; Santana-Solano, Jesús; Santillán, Moisés

    2015-01-01

    The present work is aimed at characterizing the motility of parasite T. cruzi in its epimastigote form. To that end, we recorded the trajectories of two strains of this parasite (a wild-type strain and a stable transfected strain, which contains an ectopic copy of LYT1 gene and whose motility is known to be affected). We further extracted parasite trajectories from the recorded videos, and statistically analysed the following trajectory-step features: step length, angular change of direction, longitudinal and transverse displacements with respect to the previous step, and mean square displacement. Based on the resulting observations, we developed a mathematical model to simulate parasite trajectories. The fact that the model predictions closely match most of the experimentally observed parasite-trajectory characteristics, allows us to conclude that the model is an accurate description of T. cruzi motility. PMID:26544863

  11. A Mach-Zender Holographic Microscope for Quantifying Bacterial Motility

    NASA Astrophysics Data System (ADS)

    Niraula, B.; Nadeau, J. L.; Serabyn, E.; Wallace, J. K.; Liewer, K.; Kuhn, J.; Graff, E.; Lindensmith, C.

    2014-12-01

    New microscopic techniques have revolutionized cell biology over the past two decades. However, there are still biological processes whose details elude us, especially those involving motility: e.g. feeding behavior of microorganisms in the ocean, or migration of cancer cells to form metastases. Imaging prokaryotes, which range in size from several hundred nm to a few microns, is especially challenging. An emerging technique to address these issues is Digital Holographic Microscopy (DHM). DHM is an imaging technique that uses the interference of light to record and reproduce three-dimensional magnified images of objects. This approach has several advantages over ordinary brightfield microscopy for fieldwork: a larger depth of field, hands-off operation, robustness regarding environmental conditions, and large sampling volumes with quantitative 3D records of motility behavior. Despite these promising features, real-time DHM was thought to be impractical for technological and computational reasons until recently, and there has so far been very limited application of DHM to biology. Most existing instruments are limited in performance by their particular (e.g. in-line, lens-less, phase-shifting) approach to holography. These limitations can be mitigated with an off-axis dual-path configuration. Here we describe the design and implementation of a design for a Mach-Zehnder-type holographic microscope with diffraction-limited lateral resolution, with intended applications in environmental microbiology. We have achieved sub-micron resolution and three-dimensional tracking of prokaryotic and eukaryotic test strains designed to represent different modes and speeds of microbial motility. Prokaryotes are Escherichia coli, Vibrio alginolyticus, and Bacillus subtilis. Each shows a characteristic motility pattern, as we illustrate in holographic videos in sample chambers 0.6 mm in depth. The ability to establish gradients of attractants with bacterial taxis towards the

  12. Light regulation of swarming motility in Pseudomonas syringae integrates signaling pathways mediated by a bacteriophytochrome and a LOV protein.

    PubMed

    Wu, Liang; McGrane, Regina S; Beattie, Gwyn A

    2013-06-11

    The biological and regulatory roles of photosensory proteins are poorly understood for nonphotosynthetic bacteria. The foliar bacterial pathogen Pseudomonas syringae has three photosensory protein-encoding genes that are predicted to encode the blue-light-sensing LOV (light, oxygen, or voltage) histidine kinase (LOV-HK) and two red/far-red-light-sensing bacteriophytochromes, BphP1 and BphP2. We provide evidence that LOV-HK and BphP1 form an integrated network that regulates swarming motility in response to multiple light wavelengths. The swarming motility of P. syringae B728a deletion mutants indicated that LOV-HK positively regulates swarming motility in response to blue light and BphP1 negatively regulates swarming motility in response to red and far-red light. BphP2 does not detectably regulate swarming motility. The histidine kinase activity of each LOV-HK and BphP1 is required for this regulation based on the loss of complementation upon mutation of residues key to their kinase activity. Surprisingly, mutants lacking both lov and bphP1 were similar in motility to a bphP1 single mutant in blue light, indicating that the loss of bphP1 is epistatic to the loss of lov and also that BphP1 unexpectedly responds to blue light. Moreover, whereas expression of bphP1 did not alter motility under blue light in a bphP1 mutant, it reduced motility in a mutant lacking lov and bphP1, demonstrating that LOV-HK positively regulates motility by suppressing negative regulation by BphP1. These results are the first to show cross talk between the LOV protein and phytochrome signaling pathways in bacteria, and the similarity of this regulatory network to that of photoreceptors in plants suggests a possible common ancestry. IMPORTANCE Photosensory proteins enable organisms to perceive and respond to light. The biological and ecological roles of these proteins in nonphotosynthetic bacteria are largely unknown. This study discovered that a blue-light-sensing LOV (light, oxygen, or

  13. Electrical Signaling in Motile and Primary Cilia

    PubMed Central

    Kleene, Steven J.; Van Houten, Judith L.

    2014-01-01

    Cilia are highly conserved for their structure and also for their sensory functions. They serve as antennae for extracellular information. Whether the cilia are motile or not, they respond to environmental mechanical and chemical stimuli and send signals to the cell body. The information from extracellular stimuli is commonly converted to electrical signals through the repertoire of ion-conducting channels in the ciliary membrane, which results in changes in concentrations of ions, especially calcium ions, in the cilia. These changes, in turn, affect motility and the ability of the signaling pathways in the cilia and cell body to carry on the signal transduction. We review here the activities of ion channels in cilia in animals from protists to vertebrates. PMID:25892740

  14. Hydrodynamic Contributions to Amoeboid Cell Motility

    NASA Astrophysics Data System (ADS)

    Lewis, Owen; Guy, Robert

    2012-11-01

    Understanding the methods by which cells move is a fundamental problem in modern biology. Recent evidence has shown that the fluid dynamics of cytoplasm can play a vital role in cellular motility. The slime mold Physarum polycephalum provides an excellent model organism for the study of amoeboid motion. In this research, we use a simply analytic model in conjuction with computational experiments to investigate intracellular fluid flow in a simple model of Physarum. Of particlar interest are stresses generated by cytoplasmic flow which may be used to aid in cellular motility. In our numerical model, the Immersed Boundary Method is used to account for such stresses. We investigate the relationship between contraction waves, flow waves, adhesion, and locomotive forces in an attempt to characterize conditions necessary to generate directed motion.

  15. Hydrodynamic Contributions to Amoeboid Cell Motility

    NASA Astrophysics Data System (ADS)

    Lewis, Owen; Guy, Robert

    2011-11-01

    Understanding the methods by which cells move is a fundamental problem in modern biology. Recent evidence has shown that the fluid dynamics of cytoplasm can play a vital role in cellular motility. The slime mold Physarum polycephalum provides an excellent model organism for the study of amoeboid motion. In this research, we use both analytic and computational models to investigate intracellular fluid flow in a simple model of Physarum. In both models, of we are specifically interested in stresses generated by cytoplasmic flow which act in the direction of cellular motility. In our numerical model, the Immersed Boundary Method is used to account for such stresses. We investigate the relationship between contraction waves, low waves and locomotive forces, and attempt characterize conditions necessary to generate directed motion.

  16. Uterine motility in patients with bicornuate uterus.

    PubMed

    Oliva, G C; Fratoni, A; Genova, M; Romanini, C

    1992-01-01

    This study analyzes uterine motility in 12 women with a bicornuate uterus using the results of the recordings of endo-uterine pressure, obtained with two balloon-closed catheters. Seven patients had symmetric uterine cavities, while the rest (5 patient) had very dissimilar ones. The registration of the uterine motility was carried out during various phases of the cycle and after the administration of two drugs (oxitocin and methylergobasine), with the following results: the bicornuate uterus has a spontaneous activity similar to that of a normal uterus. A similar contractile response was observed in the uteri with two anatomically symmetric horns, whereas a dissimilar response was typical of the uteri with marked anatomic differences between the two horns.

  17. Symbiosis and the origin of eukaryotic motility

    NASA Technical Reports Server (NTRS)

    Margulis, L.; Hinkle, G.

    1991-01-01

    Ongoing work to test the hypothesis of the origin of eukaryotic cell organelles by microbial symbioses is discussed. Because of the widespread acceptance of the serial endosymbiotic theory (SET) of the origin of plastids and mitochondria, the idea of the symbiotic origin of the centrioles and axonemes for spirochete bacteria motility symbiosis was tested. Intracellular microtubular systems are purported to derive from symbiotic associations between ancestral eukaryotic cells and motile bacteria. Four lines of approach to this problem are being pursued: (1) cloning the gene of a tubulin-like protein discovered in Spirocheata bajacaliforniesis; (2) seeking axoneme proteins in spirochets by antibody cross-reaction; (3) attempting to cultivate larger, free-living spirochetes; and (4) studying in detail spirochetes (e.g., Cristispira) symbiotic with marine animals. Other aspects of the investigation are presented.

  18. A Comprehensive Genetic Characterization of Bacterial Motility

    PubMed Central

    Girgis, Hany S; Liu, Yirchung; Ryu, William S; Tavazoie, Saeed

    2007-01-01

    We have developed a powerful experimental framework that combines competitive selection and microarray-based genetic footprinting to comprehensively reveal the genetic basis of bacterial behaviors. Application of this method to Escherichia coli motility identifies 95% of the known flagellar and chemotaxis genes, and reveals three dozen novel loci that, to varying degrees and through diverse mechanisms, affect motility. To probe the network context in which these genes function, we developed a method that uncovers genome-wide epistatic interactions through comprehensive analyses of double-mutant phenotypes. This allows us to place the novel genes within the context of signaling and regulatory networks, including the Rcs phosphorelay pathway and the cyclic di-GMP second-messenger system. This unifying framework enables sensitive and comprehensive genetic characterization of complex behaviors across the microbial biosphere. PMID:17941710

  19. Endocytic reawakening of motility in jammed epithelia.

    PubMed

    Malinverno, Chiara; Corallino, Salvatore; Giavazzi, Fabio; Bergert, Martin; Li, Qingsen; Leoni, Marco; Disanza, Andrea; Frittoli, Emanuela; Oldani, Amanda; Martini, Emanuele; Lendenmann, Tobias; Deflorian, Gianluca; Beznoussenko, Galina V; Poulikakos, Dimos; Ong, Kok Haur; Uroz, Marina; Trepat, Xavier; Parazzoli, Dario; Maiuri, Paolo; Yu, Weimiao; Ferrari, Aldo; Cerbino, Roberto; Scita, Giorgio

    2017-01-30

    Dynamics of epithelial monolayers has recently been interpreted in terms of a jamming or rigidity transition. How cells control such phase transitions is, however, unknown. Here we show that RAB5A, a key endocytic protein, is sufficient to induce large-scale, coordinated motility over tens of cells, and ballistic motion in otherwise kinetically arrested monolayers. This is linked to increased traction forces and to the extension of cell protrusions, which align with local velocity. Molecularly, impairing endocytosis, macropinocytosis or increasing fluid efflux abrogates RAB5A-induced collective motility. A simple model based on mechanical junctional tension and an active cell reorientation mechanism for the velocity of self-propelled cells identifies regimes of monolayer dynamics that explain endocytic reawakening of locomotion in terms of a combination of large-scale directed migration and local unjamming. These changes in multicellular dynamics enable collectives to migrate under physical constraints and may be exploited by tumours for interstitial dissemination.

  20. Regulatory mimicry in Listeria monocytogenes actin-based motility

    PubMed Central

    Chong, Ryan; Swiss, Rachel; Briones, Gabriel; Stone, Kathryn L.; Gulcicek, Erol E.; Agaisse, Hervé

    2009-01-01

    Summary The actin-based motility of the intracellular pathogen Listeria monocytogenes relies on ActA, a bacterial factor mimicking the activity of host cell nucleation-promoting factors of the WASP/WAVE family. The activity of WASP and WAVE is tightly regulated in cells. However, it is not known whether the activity of ActA is regulated upon L. monocytogenes infection. Here, we used an RNAi-based genetic approach in combination with computer-assisted image analysis to investigate the role of host factors in L. monocytogenes spread from cell to cell. We showed that the host cell serine/threonine kinase CK2 is required for efficient actin tail formation. We demonstrated that, similar to WASP and WAVE, the affinity of ActA for the ARP2/3 complex is regulated by CK2-mediated phosphorylation. We also demonstrated the importance of this regulatory mechanism in a mouse model of infection. Our work suggests that ActA is a bacterial virulence factor that not only displays a structural mimic of the VCA domain of WASP/WAVE family members, but also co-opted CK2 as the host cell factor regulating its activity, a form of mimicry that we refer to as regulatory mimicry. We present comparative evidence supporting the notion that unrelated pathogens displaying actin-based motility may have evolved a similar strategy. PMID:19748468

  1. Regulation of gastrointestinal motility--insights from smooth muscle biology.

    PubMed

    Sanders, Kenton M; Koh, Sang Don; Ro, Seungil; Ward, Sean M

    2012-11-01

    Gastrointestinal motility results from coordinated contractions of the tunica muscularis, the muscular layers of the alimentary canal. Throughout most of the gastrointestinal tract, smooth muscles are organized into two layers of circularly or longitudinally oriented muscle bundles. Smooth muscle cells form electrical and mechanical junctions between cells that facilitate coordination of contractions. Excitation-contraction coupling occurs by Ca(2+) entry via ion channels in the plasma membrane, leading to a rise in intracellular Ca(2+). Ca(2+) binding to calmodulin activates myosin light chain kinase; subsequent phosphorylation of myosin initiates cross-bridge cycling. Myosin phosphatase dephosphorylates myosin to relax muscles, and a process known as Ca(2+) sensitization regulates the activity of the phosphatase. Gastrointestinal smooth muscles are 'autonomous' and generate spontaneous electrical activity (slow waves) that does not depend upon input from nerves. Intrinsic pacemaker activity comes from interstitial cells of Cajal, which are electrically coupled to smooth muscle cells. Patterns of contractile activity in gastrointestinal muscles are determined by inputs from enteric motor neurons that innervate smooth muscle cells and interstitial cells. Here we provide an overview of the cells and mechanisms that generate smooth muscle contractile behaviour and gastrointestinal motility.

  2. Immobilization of motile bacterial cells via dip-pen nanolithography

    NASA Astrophysics Data System (ADS)

    Nyamjav, Dorjderem; Rozhok, Sergey; Holz, Richard C.

    2010-06-01

    A strategy to bind bacterial cells to surfaces in a directed fashion via dip-pen nanolithography (DPN) is presented. Cellular attachment to pre-designed DPN generated microarrays was found to be dependent on the shape and size of the surface feature. While this observation is likely due in part to a dense, well formed mercaptohexadecanoic acid (MHA) monolayer generated via DPN, it may also simply be due to the physical shape of the surface structure. Motile Pseudomonas aeruginosa bacterial cells were observed to bind to DPN generated mercaptohexadecanoic acid/poly-L-lysine (MHA/PLL) line patterns, 'blocks' made up of eight lines with 100 nm spacings, with ~ 80% occupancy. Cellular binding to these 'block' surface structures occurs via an electrostatic interaction between negatively charged groups on the bacterial cell surface and positively charged poly-L-lysine (PLL) assemblies. These data indicate that these DPN generated 'block' surface structures provide a promising footprint for the attachment of motile bacterial cells that may find utility in cell based biosensors or single cell studies.

  3. Cell motility: Combining experiments with modeling

    NASA Astrophysics Data System (ADS)

    Rappel, Wouter-Jan

    2013-03-01

    Cell migration and motility is a pervasive process in many biology systems. It involves intra-cellular signal transduction pathways that eventually lead to membrane extension and contraction. Here we describe our efforts to combine quantitative experiments with theoretical and computational modeling to gain fundamental insights into eukaryotic cell motion. In particular, we will focus on the amoeboid motion of Dictyostelium discoideum cells. This work is supported by the National Institutes of Health (P01 GM078586)

  4. Motility-indole-lysine-sulfide medium.

    PubMed

    Ederer, G M; Lund, M E; Blazevic, D J; Reller, L B; Mirrett, S

    1975-09-01

    A medium designed for the detection of motility, indole, lysine decarboxylase and deaminase reactions, and H2S production was devised and evaluated. Results, using 157 strains of enteric pathogens, were in agreement with reference methods. When 300 isolates from fecal cultures were screened using this medium, Shigella was easily differentiated from Escherichia and more of the Proteus species, especially P. morganii, could be eliminated from further study.

  5. Influence of twitching and swarming motilities on biofilm formation in Pseudomonas strains.

    PubMed

    Otton, Letícia Muner; da Silva Campos, Marina; Meneghetti, Karine Lena; Corção, Gertrudes

    2017-02-15

    The genus Pseudomonas mainly includes opportunistic pathogens that rely on type IV pili as an important virulence factor, which is associated with adherence and biofilm formation. Pseudomonas infections are well known to be persistent and resilient in nature largely because of the tendency of the species to form biofilms. This study aimed at analyzing environmental strains of Pseudomonas genus with respect to their ability to execute twitching and swarming motilities as well as with respect to their ability to form biofilms both in the presence as well as in the absence of furanone, a substance that has the potential to prevent the formation of biofilms. Strains of Pseudomonas aeruginosa and strains belonging to other species of the genus were analyzed. Twitching and swarming motility assays and biofilm-formation assays, both in the presence as well as in the absence of furanone, were performed. In twitching assay strains belonging to P. aeruginosa outperformed those belonging to other species. Interestingly, it was seen that the presence of furanone had a negative impact on formation of twitching and swarming motility zones. In the case of biofilm assays, it was observed that the presence of furanone resulted in an observable decrease in the degree of adhesion in 30% of the analyzed strains. Thus, from our results, it can be concluded that, as compared to other species, the strains belonging to P. aeruginosa exhibit a higher potential for twitching motility and similar performance in swarming motility and biofilm formation. It can also be concluded that furanone has the potential to interfere with both motilities as well as with biofilm formation.

  6. Hyaluronan stimulates pancreatic cancer cell motility

    PubMed Central

    Cheng, Xiao-Bo; Kohi, Shiro; Koga, Atsuhiro; Hirata, Keiji; Sato, Norihiro

    2016-01-01

    Hyaluronan (HA) accumulates in pancreatic ductal adenocarcinoma (PDAC), but functional significance of HA in the aggressive phenotype remains unknown. We used different models to investigate the effect of HA on PDAC cell motility by wound healing and transwell migration assay. Changes in cell motility were examined in 8 PDAC cell lines in response to inhibition of HA production by treatment with 4-methylumbelliferone (4-MU) and to promotion by treatment with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) or by co-culture with tumor-derived stromal fibroblasts. We also investigated changes in cell motility by adding exogenous HA. Additionally, mRNA expressions of hyaluronan synthases and hyaluronidases were examined using real time RT-PCR. Inhibition of HA by 4-MU significantly decreased the migration, whereas promotion of HA by TPA or co-culture with tumor-derived fibroblasts significantly increased the migration of PDAC cells. The changes in HA production by these treatments tended to be associated with changes in HAS3 mRNA expression. Furthermore, addition of exogenous HA, especially low-molecular-weight HA, significantly increased the migration of PDAC cells. These findings suggest that HA stimulates PDAC cell migration and thus represents an ideal therapeutic target to prevent invasion and metastasis. PMID:26684359

  7. Effect of total laryngectomy on esophageal motility

    SciTech Connect

    Hanks, J.B.; Fisher, S.R.; Meyers, W.C.; Christian, K.C.; Postlethwait, R.W.; Jones, R.S.

    1981-01-01

    Total laryngectomy for cancer can result in dysphagia and altered esophageal motility. Manometric changes in the upper esophageal sphincter (UES), and in proximal and distal esophageal function have been reported. However, most studies have failed to take into account radiation therapy and appropriate controls. We selected ten male patients (54.3 +/- 1.9 yr) for longitudinal manometric evaluation prior to laryngectomy then at two weeks and again six months later. No patient received preoperative radiation therapy, had a previous history of esophageal surgery, or developed a postoperative wound infection or fistula. Seven of ten patients had positive nodes and received 6,000-6,600 rads postoperative radiation therapy. Preoperatively 4 of 10 patients complained of dysphagia which did not significantly change following surgery and radiation. Two of three patients who did not complain of dysphagia preoperatively and received radiation postoperatively developed dysphagia. No patient without dysphagia preoperatively who received no radiation therapy developed symptoms. Our studies show that laryngectomy causes alterations in the UES resting and peak pressures but not in the proximal or distal esophagus, or the lower esophageal sphincter. These data also imply radiation therapy may be associated with progressive alterations in motility and symptomatology. Further study regarding the effects of radiation on esophageal motility and function are urged.

  8. Motility of active fluid drops on surfaces

    NASA Astrophysics Data System (ADS)

    Khoromskaia, Diana; Alexander, Gareth P.

    2015-12-01

    Drops of active liquid crystal have recently shown the ability to self-propel, which was associated with topological defects in the orientation of active filaments [Sanchez et al., Nature 491, 431 (2013), 10.1038/nature11591]. Here, we study the onset and different aspects of motility of a three-dimensional drop of active fluid on a planar surface. We analyze theoretically how motility is affected by orientation profiles with defects of various types and locations, by the shape of the drop, and by surface friction at the substrate. In the scope of a thin drop approximation, we derive exact expressions for the flow in the drop that is generated by a given orientation profile. The flow has a natural decomposition into terms that depend entirely on the geometrical properties of the orientation profile, i.e., its bend and splay, and a term coupling the orientation to the shape of the drop. We find that asymmetric splay or bend generates a directed bulk flow and enables the drop to move, with maximal speeds achieved when the splay or bend is induced by a topological defect in the interior of the drop. In motile drops the direction and speed of self-propulsion is controlled by friction at the substrate.

  9. Swimming Motility Reduces Deposition to Silica Surfaces

    SciTech Connect

    Lu, Nanxi; Massoudieh, Arash; Liang, Xiaomeng; Hu, Dehong; Kamai, Tamir; Ginn, Timothy R.; Zilles, Julie L.; Nguyen, Thanh H.

    2015-01-01

    The role of swimming motility on bacterial transport and fate in porous media was evaluated. We present microscopic evidence showing that strong swimming motility reduces attachment of Azotobacter vinelandii cells to silica surfaces. Applying global and cluster statistical analyses to microscopic videos taken under non-flow conditions, wild type, flagellated A. vinelandii strain DJ showed strong swimming ability with an average speed of 13.1 μm/s, DJ77 showed impaired swimming averaged at 8.7 μm/s, and both the non-flagellated JZ52 and chemically treated DJ cells were non-motile. Quantitative analyses of trajectories observed at different distances above the collector of a radial stagnation point flow cell (RSPF) revealed that both swimming and non-swimming cells moved with the flow when at a distance of at least 20 μm from the collector surface. Near the surface, DJ cells showed both horizontal and vertical movement diverging them from reaching surfaces, while chemically treated DJ cells moved with the flow to reach surfaces, suggesting that strong swimming reduced attachment. In agreement with the RSPF results, the deposition rates obtained for two-dimensional multiple-collector micromodels were also lowest for DJ, while DJ77 and JZ52 showed similar values. Strong swimming specifically reduced deposition on the upstream surfaces of the micromodel collectors.

  10. Gastrointestinal motility testing--a personal perspective.

    PubMed

    Quigley, E M

    1995-01-01

    The role of motility tests in the evaluation of some common disorders in which motility has been assumed to play a role is reviewed. Three separate areas, non-cardiac chest pain, constipation and the irritable bowel syndrome are discussed. In each area, considerable difficulty in the clinical definition of these disorders persists and presents a major obstacle to the evaluation of diagnostic tests. With regard to non-cardiac chest pain, it is apparent that gastro-oesophageal reflux and sensory/perception abnormalities, rather than dysmotility, are the predominant factors, and investigations should take account of this. While studies of colonic and small intestinal motility have demonstrated various abnormal patterns in patients described as suffering from the irritable bowel syndrome, the specificity of any of these motor 'abnormalities' remains uncertain, and manometry cannot be recommended as a diagnostic tool in this context. Considerable advances have been made in our understanding of gut motor physiology and in our ability to accurately record motor function in man, the basic pathophysiology of many 'functional' gut syndromes remains unclear, and the role of dysmotility, in particular, poorly defined.

  11. Physics of protein motility and motor proteins

    NASA Astrophysics Data System (ADS)

    Kolomeisky, Anatoly B.

    2013-09-01

    Motor proteins are enzymatic molecules that transform chemical energy into mechanical motion and work. They are critically important for supporting various cellular activities and functions. In the last 15 years significant progress in understanding the functioning of motor proteins has been achieved due to revolutionary breakthroughs in single-molecule experimental techniques and strong advances in theoretical modelling. However, microscopic mechanisms of protein motility are still not well explained, and the collective efforts of many scientists are needed in order to solve these complex problems. In this special section the reader will find the latest advances on the difficult road to mapping motor proteins dynamics in various systems. Recent experimental developments have allowed researchers to monitor and to influence the activity of single motor proteins with a high spatial and temporal resolution. It has stimulated significant theoretical efforts to understand the non-equilibrium nature of protein motility phenomena. The latest results from all these advances are presented and discussed in this special section. We would like to thank the scientists from all over the world who have reported their latest research results for this special section. We are also grateful to the staff and editors of Journal of Physics: Condensed Matter for their invaluable help in handling all the administrative and refereeing activities. The field of motor proteins and protein motility is fast moving, and we hope that this collection of articles will be a useful source of information in this highly interdisciplinary area. Physics of protein motility and motor proteins contents Physics of protein motility and motor proteinsAnatoly B Kolomeisky Identification of unique interactions between the flexible linker and the RecA-like domains of DEAD-box helicase Mss116 Yuan Zhang, Mirkó Palla, Andrew Sun and Jung-Chi Liao The load dependence of the physical properties of a molecular motor

  12. The Wireless Motility Capsule: a One-Stop Shop for the Evaluation of GI Motility Disorders.

    PubMed

    Saad, Richard J

    2016-03-01

    The wireless motility and pH capsule (WMC) provides an office-based test to simultaneously assess both regional and whole gut transit. Ingestion of this non-digestible capsule capable of measuring temperature, pH, and the pressure of its immediate surroundings allows for the measurement of gastric, small bowel, and colonic transit times in an ambulatory setting. Approved by the US Food and Drug Administration for the evaluation of suspected conditions of delayed gastric emptying and the evaluation of colonic transit in chronic idiopathic constipation, WMC should be considered in suspected gastrointestinal motility disorders as it provides a single study capable of simultaneously assessing for regional, multiregional, or generalized motility disorders. Specific indications for testing with the WMC should include the evaluation of suspect cases of gastroparesis, small bowel dysmotility, and slow transit constipation, as well as symptom syndromes suggestive of a multiregional or generalized gastrointestinal transit delay.

  13. First identification of proteins involved in motility of Mycoplasma gallisepticum.

    PubMed

    Indikova, Ivana; Vronka, Martin; Szostak, Michael P

    2014-10-17

    Mycoplasma gallisepticum, the most pathogenic mycoplasma in poultry, is able to glide over solid surfaces. Although this gliding motility was first observed in 1968, no specific protein has yet been shown to be involved in gliding. We examined M. gallisepticum strains and clonal variants for motility and found that the cytadherence proteins GapA and CrmA were required for gliding. Loss of GapA or CrmA resulted in the loss of motility and hemadsorption and led to drastic changes in the characteristic flask-shape of the cells. To identify further genes involved in motility, a transposon mutant library of M. gallisepticum was generated and screened for motility-deficient mutants, using a screening assay based on colony morphology. Motility-deficient mutants had transposon insertions in gapA and the neighbouring downstream gene crmA. In addition, insertions were seen in gene mgc2, immediately upstream of gapA, in two motility-deficient mutants. In contrast to the GapA/CrmA mutants, the mgc2 motility mutants still possessed the ability to hemadsorb. Complementation of these mutants with a mgc2-hexahistidine fusion gene restored the motile phenotype. This is the first report assigning specific M. gallisepticum proteins to involvement in gliding motility.

  14. A mechanical model for the motility of actin filaments on myosin

    NASA Astrophysics Data System (ADS)

    Nicolau, Dan V., Jr.; Fulga, Florin; Nicolau, Dan V.

    2004-03-01

    The interaction of actin filaments with myosin is crucial to cell motility, muscular contraction, cell division and other processes. The in vitro motility assay involves the motion of actin filaments on a substrate coated with myosin, and is used extensively to investigate the dynamics of the actomyosin system. Following on from previous work, we propose a new mechanical model of actin motility on myosin, wherein a filament is modeled as a chain of beads connected by harmonic springs. This imposes a limitation on the "stretching" of the filament. The rotation of one bead with respect to its neighbours is also constrained in similar way. We implemented this model and used Monte Carlo simulations to determine whether it can predict the directionality of filament motion. The principal advantages of this model over our previous one are that we have removed the empirically correct but artificial assumption that the filament moves like a "worm" i.e. the head determines the direction of movement and the rest of the filament "follows" the head as well as the inclusion of dependencies on experimental rate constants (and so also on e.g. ATP concentration) via the cross-bridge cycle.

  15. Motility, chemotaxis and aerotaxis contribute to competitiveness during bacterial pellicle biofilm development

    PubMed Central

    Gallegos-Monterrosa, Ramses; Price-Whelan, Alexa; Kolter, Roberto; Dietrich, Lars E. P.; Kovács, Ákos T.

    2016-01-01

    Biofilm formation is a complex process involving various signaling pathways and changes in gene expression. Many of the sensory mechanisms and regulatory cascades involved have been defined for biofilms formed by diverse organisms attached to solid surfaces. By comparison, our knowledge of the basic mechanisms underlying the formation of biofilms at air-liquid interfaces, i.e. pellicles, is much less complete. In particular, the roles of flagella have been studied in multiple solid-surface biofilm models, but remain largely undefined for pellicles. In this work, we characterize the contributions of flagellum-based motility, chemotaxis and oxygen sensing to pellicle formation in the Gram-positive Bacillus subtilis. We confirm that flagellum-based motility is involved in, but is not absolutely essential for, B. subtilis pellicle formation. Further, we show that flagellum-based motility, chemotaxis, and oxygen sensing are important for successful competition during B. subtilis pellicle formation. We report that flagellum-based motility similarly contributes to pellicle formation and fitness in competition assays in the Gram-negative Pseudomonas aeruginosa. Time-lapse imaging of static liquid cultures demonstrates that in both B. subtilis and P. aeruginosa, a turbulent flow forms in the tube and a zone of clearing appears below the air-liquid interface just before the formation of the pellicle, but only in strains that have flagella. PMID:26122431

  16. Cell motility and local viscoelasticity of fibroblasts.

    PubMed

    Park, S; Koch, D; Cardenas, R; Käs, J; Shih, C K

    2005-12-01

    Viscoelastic changes of the lamellipodial actin cytoskeleton are a fundamental element of cell motility. Thus, the correlation between the local viscoelastic properties of the lamellipodium (including the transitional region to the cell body) and the speed of lamellipodial extension is studied for normal and malignantly transformed fibroblasts. Using our atomic force microscopy-based microrheology technique, we found different mechanical properties between the lamellipodia of malignantly transformed fibroblasts (H-ras transformed and SV-T2 fibroblasts) and normal fibroblasts (BALB 3T3 fibroblasts). The average elastic constants, K, in the leading edge of SV-T2 fibroblasts (0.48 +/- 0.51 kPa) and of H-ras transformed fibroblasts (0.42 +/- 0.35 kPa) are significantly lower than that of BALB 3T3 fibroblasts (1.01 +/- 0.40 kPa). The analysis of time-lapse phase contrast images shows that the decrease in the elastic constant, K, for malignantly transformed fibroblasts is correlated with the enhanced motility of the lamellipodium. The measured mean speeds are 6.1 +/- 4.5 microm/h for BALB 3T3 fibroblasts, 13.1 +/- 5.2 microm/h for SV-T2 fibroblasts, and 26.2 +/- 11.5 microm/h for H-ras fibroblasts. Furthermore, the elastic constant, K, increases toward the cell body in many instances which coincide with an increase in actin filament density toward the cell body. The correlation between the enhanced motility and the decrease in viscoelastic moduli supports the Elastic Brownian Ratchet model for driving lamellipodia extension.

  17. Involvement of the Type IX Secretion System in Capnocytophaga ochracea Gliding Motility and Biofilm Formation

    PubMed Central

    Kita, Daichi; Shibata, Satoshi; Kikuchi, Yuichiro; Kokubu, Eitoyo; Nakayama, Koji; Saito, Atsushi

    2016-01-01

    Capnocytophaga ochracea is a Gram-negative, rod-shaped bacterium that demonstrates gliding motility when cultured on solid agar surfaces. C. ochracea possesses the ability to form biofilms; however, factors involved in biofilm formation by this bacterium are unclear. A type IX secretion system (T9SS) in Flavobacterium johnsoniae was shown to be involved in the transport of proteins (e.g., several adhesins) to the cell surface. Genes orthologous to those encoding T9SS proteins in F. johnsoniae have been identified in the genome of C. ochracea; therefore, the T9SS may be involved in biofilm formation by C. ochracea. Here we constructed three ortholog-deficient C. ochracea mutants lacking sprB (which encodes a gliding motility adhesin) or gldK or sprT (which encode T9SS proteins in F. johnsoniae). Gliding motility was lost in each mutant, suggesting that, in C. ochracea, the proteins encoded by sprB, gldK, and sprT are necessary for gliding motility, and SprB is transported to the cell surface by the T9SS. For the ΔgldK, ΔsprT, and ΔsprB strains, the amounts of crystal violet-associated biofilm, relative to wild-type values, were 49%, 34%, and 65%, respectively, at 48 h. Confocal laser scanning and scanning electron microscopy revealed that the biofilms formed by wild-type C. ochracea were denser and bacterial cells were closer together than in those formed by the mutant strains. Together, these results indicate that proteins exported by the T9SS are key elements of the gliding motility and biofilm formation of C. ochracea. PMID:26729712

  18. Dynamic Clustering in Suspension of Motile Bacteria

    NASA Astrophysics Data System (ADS)

    Zhang, Hepeng; Chen, Xiao; Yang, Xiang; Yang, Mingcheng

    2015-03-01

    Bacteria suspension exhibits a wide range of collective phenomena arising from interactions between individual cells. Here we investigate dynamic clusters of motile bacteria near an air-liquid interface. Cell in a cluster orient its flagella perpendicular to the interface and generate attractive radial fluid flow that leads to cluster formation. Rotating cell also creates tangential forces on neighbors that sets clusters into counter-clockwise rotation. We construct a numerical model of self-propelled particles that interact via pair-wise forces extracted from hydrodynamic calculations; such a model reproduces many properties of observed cluster dynamics.

  19. Gastrointestinal motility in space motion sickness

    NASA Technical Reports Server (NTRS)

    Thornton, William E.; Linder, Barry J.; Moore, Thomas P.; Pool, Sam L.

    1987-01-01

    Gastrointestinal symptoms in space motion sickness (SMS) are significantly different from those in ordinary motion sickness (MS). Recording and tabulation of sounds was the only technique that could be used as a measure of motility during spaceflight operations. There were 17 subjects, six unaffected by SMS, who made ambulatory recordings preflight and inflight. With one exception, all those affected had sharply reduced sounds, while those unaffected had increases or moderate reductions. The mechanism of vomiting in SMS appears to be secondary to this ileus, in contrast to vomiting in ordinary MS, where the emesis center is thought to be directly triggered by the vestibular system.

  20. The unique paradigm of spirochete motility and chemotaxis.

    PubMed

    Charon, Nyles W; Cockburn, Andrew; Li, Chunhao; Liu, Jun; Miller, Kelly A; Miller, Michael R; Motaleb, Md A; Wolgemuth, Charles W

    2012-01-01

    Spirochete motility is enigmatic: It differs from the motility of most other bacteria in that the entire bacterium is involved in translocation in the absence of external appendages. Using the Lyme disease spirochete Borrelia burgdorferi (Bb) as a model system, we explore the current research on spirochete motility and chemotaxis. Bb has periplasmic flagella (PFs) subterminally attached to each end of the protoplasmic cell cylinder, and surrounding the cell is an outer membrane. These internal helix-shaped PFs allow the spirochete to swim by generating backward-moving waves by rotation. Exciting advances using cryoelectron tomography are presented with respect to in situ analysis of cell, PF, and motor structure. In addition, advances in the dynamics of motility, chemotaxis, gene regulation, and the role of motility and chemotaxis in the life cycle of Bb are summarized. The results indicate that the motility paradigms of flagellated bacteria do not apply to these unique bacteria.

  1. Swimming and swarming motility properties of peanut-nodulating rhizobia.

    PubMed

    Vicario, Julio C; Dardanelli, Marta S; Giordano, Walter

    2015-01-01

    Motility allows populations of bacteria to rapidly reach and colonize new microniches or microhabitats. The motility of rhizobia (symbiotic nitrogen-fixing bacteria that nodulate legume roots) is an important factor determining their competitive success. We evaluated the effects of temperature, incubation time, and seed exudates on swimming and swarming motility of five strains of Bradyrhizobium sp. (peanut-nodulating rhizobia). Swimming motility was increased by exudate exposure for all strains except native Pc34. In contrast, swarming motility was increased by exudate exposure for native 15A but unchanged for the other four strains. All five strains displayed the ability to differentiate into swarm cells. Morphological examination by scanning electron microscopy showed that the length of the swarm cells was variable, but generally greater than that of vegetative cells. Our findings suggest the importance of differential motility properties of peanut-nodulating rhizobial strains during agricultural inoculation and early steps of symbiotic interaction with the host.

  2. What Counts as Inclusion?

    ERIC Educational Resources Information Center

    Walton, E.; Nel, N.

    2012-01-01

    In the years since the publication in South Africa of White Paper Six: Special needs education (Department of Education (DoE) 2001) various schools in the state and independent sectors have begun to implement inclusive policies and practices. With reference to the Guidelines for full-service/inclusive schools issued in 2009, and by discussing a…

  3. Understanding Inclusion in Cyprus

    ERIC Educational Resources Information Center

    Mamas, Christoforos

    2013-01-01

    This paper provides a framework for understanding inclusion in Cyprus. The evidence base is the result of a six-month qualitative research study in five Cypriot mainstream primary schools. Despite the rhetoric in favour of inclusion, it seems that the Cypriot educational system is still highly segregating in its philosophy and does not fully…

  4. Inclusive Services Innovation Configuration

    ERIC Educational Resources Information Center

    Holdheide, Lynn R.; Reschly, Daniel J.

    2011-01-01

    Teacher preparation to deliver inclusive services to students with disabilities is increasingly important because of changes in law and policy emphasizing student access to, and achievement in, the general education curriculum. This innovation configuration identifies the components of inclusive services that should be incorporated in teacher…

  5. Handbook for Successful Inclusion.

    ERIC Educational Resources Information Center

    Kochhar, Carol A.; West, Lynda L.

    This manual is intended to help regular and special educators and related professionals to better serve special learners in inclusive settings through identifying practical strategies for the classroom and school, and techniques for overcoming barriers to inclusion. The manual is written in a question-and-answer format. The first chapter addresses…

  6. Learning Styles and Inclusion

    ERIC Educational Resources Information Center

    Reid, Gavin

    2005-01-01

    This book is about learning styles and inclusion, but essentially it is about learning, and how to make learning more effective for all learners. To recognise the needs of learners as well as those of teachers, and at the same time appreciate that the inclusive education environment, irrespective of its merits, will present barriers for learners,…

  7. School Inclusion Programmes (SIPS)

    ERIC Educational Resources Information Center

    Drossinou-Korea, Maria; Matousi, Dimitra; Panopoulos, Nikolaos; Paraskevopoulou, Aikaterini

    2016-01-01

    The purpose of this work was to understand the school inclusion programmes (SIPs) for students with special educational needs (SEN). The methodology was conducted in the field of special education (SE) and focuses on three case studies of students who was supported by SIPs. The Targeted, Individual, Structured, Inclusion Programme for students…

  8. Jet inclusive cross sections

    SciTech Connect

    Del Duca, V.

    1992-11-01

    Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons.

  9. Adapted Aquatics and Inclusion.

    ERIC Educational Resources Information Center

    Block, Martin E.; Conatser, Phillip

    2002-01-01

    Presents strategies and techniques to help instructors and directors promote successful inclusive aquatics programs for students with disabilities, discussing the importance of considering issues related to: teaching style, collaborative planning, goal determination, appropriate inclusive placement, personnel preparation, curriculum adaptation,…

  10. The Inclusion Facilitator's Guide

    ERIC Educational Resources Information Center

    Jorgensen, Cheryl M.; Schuh, Mary C.; Nisbet, Jan

    2005-01-01

    Inclusion facilitators are educators who do more than teach children with disabilities--they advocate for change in schools and communities, sparking a passion for inclusion in teachers, administrators, and families and giving them the practical guidance they need to make it work. This is an essential new role in today's schools, and this guide…

  11. Vinculin Proteolysis Unmasks an ActA Homolog for Actin-based Shigella Motility

    PubMed Central

    Laine, Roney O.; Zeile, William; Kang, Fan; Purich, Daniel L.; Southwick, Frederick S.

    1997-01-01

    To generate the forces needed for motility, the plasma membranes of nonmuscle cells adopt an activated state that dynamically reorganizes the actin cytoskeleton. By usurping components from focal contacts and the actin cytoskeleton, the intracellular pathogens Shigella flexneri and Listeria monocytogenes use molecular mimicry to create their own actin-based motors. We raised an antibody (designated FS-1) against the FEFPPPPTDE sequence of Listeria ActA, and this antibody: (a) localized at the trailing end of motile intracellular Shigella, (b) inhibited intracellular locomotion upon microinjection of Shigella-infected cells, and (c) cross-reacted with the proteolytically derived 90-kD human vinculin head fragment that contains the Vinc-1 oligoproline sequence, PDFPPPPPDL. Antibody FS-1 reacted only weakly with full-length vinculin, suggesting that the Vinc-1 sequence in full-length vinculin may be masked by its tail region and that this sequence is unmasked by proteolysis. Immunofluoresence staining with a monoclonal antibody against the head region of vinculin (Vin 11-5) localized to the back of motile bacteria (an identical staining pattern observed with the anti-ActA FS-1 antibody), indicating that motile bacteria attract a form of vinculin containing an unmasked Vinc-1 oligoproline sequence. Microinjection of submicromolar concentrations of a synthetic Vinc-1 peptide arrested Shigella intracellular motility, underscoring the functional importance of this sequence. Western blots revealed that Shigella infection induces vinculin proteolysis in PtK2 cells and generates p90 head fragment over the same 1–3 h time frame when intracellular bacteria move within the host cell cytoplasm. We also discovered that microinjected p90, but not full-length vinculin, accelerates rates of pathogen motility by a factor of 3 ± 0.4 in Shigella-infected PtK2 cells. These experiments suggest that vinculin p90 is a rate-limiting component in actin-based Shigella motility, and that

  12. Ineffective esophageal motility is a primary motility disorder in gastroesophageal reflux disease.

    PubMed

    Ho, Shih-Chi; Chang, Chi-Sen; Wu, Chun-Ying; Chen, Gran-Hum

    2002-03-01

    The relationship between esophageal motor abnormalities and GERD has been widely studied. The purpose of this study was to identify the prevalence of ineffective esophageal motility (IEM) in patients with GERD. In addition, we also evaluated esophageal acid exposure, acid clearance, and endoscopic esophagitis in GERD patients with IEM. Of 89 patients enrolled in this study, 47 (52.8%) were found to have nonspecific esophageal motility disorder (NEMD). Forty-four of the 47 (93.6%) patients with NEMD met the diagnostic criteria for IEM. The overall incidence of IEM in GERD patients was 49.4%. Patients with IEM had significant increases in upright and recumbent mean fraction of time pH < 4 (6.70% and 4.38%) and mean recumbent esophageal acid clearance (12.45 min/reflux) when compared to those with other motility findings. Seventeen of the 44 (39%) IEM patients did not have endoscopic esophagitis. On the other hand, 26 of the 39 (67%) patients with normal manometry had endoscopic esophagitis. We concluded that not only is the prevalence of IEM high in GERD, but also that IEM patients have more recumbent gastroesophageal reflux and delayed acid clearance. Combined with endoscopic findings, we propose that IEM can be viewed as a specific entity of primary esophageal motility disorder in patients with GERD.

  13. Primordial Compositions of Refractory Inclusions

    SciTech Connect

    Grossman, L; Simon, S B; Rai, V K; Thiemens, M H; Hutcheon, I D; Williams, R W; Galy, A; Ding, T; Fedkin, A V; Clayton, R N; Mayeda, T K

    2008-02-20

    Bulk chemical and oxygen, magnesium and silicon isotopic compositions were measured for each of 17 Types A and B refractory inclusions from CV3 chondrites. After bulk chemical compositions were corrected for non-representative sampling in the laboratory, the Mg and Si isotopic compositions of each inclusion were used to calculate its original chemical composition assuming that the heavy-isotope enrichments of these elements are due to Rayleigh fractionation that accompanied their evaporation from CMAS liquids. The resulting pre-evaporation chemical compositions are consistent with those predicted by equilibrium thermodynamic calculations for high-temperature nebular condensates but only if different inclusions condensed from nebular regions that ranged in total pressure from 10{sup -6} to 10{sup -1} bar, regardless of whether they formed in a system of solar composition or in one enriched in OC dust relative to gas by a factor of ten relative to solar composition. This is similar to the range of total pressures predicted by dynamic models of the solar nebula for regions whose temperatures are in the range of silicate condensation temperatures. Alternatively, if departure from equilibrium condensation and/or non-representative sampling of condensates in the nebula occurred, the inferred range of total pressure could be smaller. Simple kinetic modeling of evaporation successfully reproduces observed chemical compositions of most inclusions from their inferred pre-evaporation compositions, suggesting that closed-system isotopic exchange processes did not have a significant effect on their isotopic compositions. Comparison of pre-evaporation compositions with observed ones indicates that 80% of the enrichment in refractory CaO + Al{sub 2}O{sub 3} relative to more volatile MgO + SiO{sub 2} is due to initial condensation and 20% due to subsequent evaporation for both Type A and Type B inclusions.

  14. Targeting motility properties of bacteria in the development of probiotic cultures against Campylobacter jejuni in broiler chickens.

    PubMed

    Aguiar, Vivian F; Donoghue, Ann M; Arsi, Komala; Reyes-Herrera, Ixchel; Metcalf, Joel H; de los Santos, Fausto S; Blore, Pamela J; Donoghue, Dan J

    2013-05-01

    Campylobacter is the leading cause of gastroenteritis worldwide. Campylobacter is commonly present in the intestinal tract of poultry, and one strategy to reduce enteric colonization is the use of probiotic cultures. This strategy has successfully reduced enteric colonization of Salmonella, but has had limited success against Campylobacter. In an effort to improve the efficacy of probiotic cultures, we developed a novel in vitro screening technique for selecting bacterial isolates with enhanced motility. It is proposed that motility-selected bacteria have the marked ability to reach the same gastrointestinal niche in poultry and competitively reduce C. jejuni. Bacterial isolates were collected from ceca of healthy chickens, and motile isolates were identified and tested for anti-Campylobacter activity. Isolates with these properties were selected for increased motility by passing each isolate 10 times and at each passage selecting bacteria that migrated the farthest during each passage. Three bacterial isolates with the greatest motility (all Bacillus subtilis) were used alone or in combination in two chicken trials. At day of hatch, chicks were administered these isolates alone or in combination (n=10/treatment, two trials), and chicks were orally challenged with a mixture of four different wild-type strains of C. jejuni (∼10(5) CFU/mL) on day 7. Isolate 1 reduced C. jejuni colonization in both of the trials (p<0.05). A follow-up study was conducted to compare isolate 1 subjected to enhanced motility selection with its nonselected form. A reduction (p<0.05) in Campylobacter colonization was observed in all three trials in the chickens dosed using isolate with enhanced motility compared to the control and unselected isolate. These findings support the theory that the motility enhancement of potential probiotic bacteria may provide a strategy for reduction of C. jejuni in preharvest chickens.

  15. Morphed and moving: TNFα-driven motility promotes cell dissemination through MAP4K4-induced cytoskeleton remodeling

    PubMed Central

    Ma, Min; Baumgartner, Martin

    2014-01-01

    Cell dissemination from an initial site of growth is a highly coordinated and controlled process that depends on cell motility. The mechanistic principles that orchestrate cell motility, namely cell shape control, traction and force generation, are highly conserved between cells of different origins. Correspondingly, the molecular mechanisms that regulate these critical aspects of migrating cells are likely functionally conserved too. Thus, cell motility deregulation of unrelated pathogenesis could be caused and maintained by similar mechanistic principles. One such motility deregulation disorder is the leukoproliferative cattle disease Tropical Theileriosis, which is caused by the intracellular, protozoan parasite Theileria annulata. T. annulata transforms its host cell and promotes the dissemination of parasite-infected cells throughout the body of the host. An analogous condition with a fundamentally different pathogenesis is metastatic cancer, where oncogenically transformed cells disseminate from the primary tumor to form distant metastases. Common to both diseases is the dissemination of motile cells from the original site. However, unlike metastatic cancer, host cell transformation by Theileria parasites can be reverted by drug treatment and cell signaling be analyzed under transformed and non-transformed conditions. We have used this reversible transformation model and investigated parasite control of host cell motile properties in the context of inflammatory signaling in Ma M. et al. [PLoS Pathog (2014) 10: e1004003]. We found that parasite infection promotes the production of the inflammatory cytokine TNFα in the host macrophage. We demonstrated that increased TNFα triggers motile and invasive properties by enhancing actin cytoskeleton remodeling and cell motility through the ser/thr kinase MAP4K4. We concluded that inflammatory conditions resulting in increased TNFα could facilitate cell dissemination by activating the actin cytoskeleton regulatory

  16. Chemokinetic motility responses of the cyanobacterium oscillatoria terebriformis

    NASA Technical Reports Server (NTRS)

    Richardson, Laurie L.; Castenholz, Richard W.

    1989-01-01

    Oscillatoria terebriformis, a gliding, filamentous, thermophilic cyanobacterium, exhibited an inhibition of gliding motility upon exposure to fructose. The observed response was transient, and the duration of nonmotility was directly proportional to the concentration of fructose. Upon resumption of motility, the rate of motility was also inversely proportional to the concentration of fructose. Sulfide caused a similar response. The effect of sulfide was specific and not due to either anoxia or negative redox potential. Exposure to glucose, acetate, lactate, or mat interstitial water did not elicit any motility response.

  17. Rational pharmacotherapy of gastrointestinal motility disorders.

    PubMed

    Demol, P; Ruoff, H J; Weihrauch, T R

    1989-04-01

    Nervous control of gastrointestinal motility is extremely complex, is regulated by the enteric system, the "brain of the gut", and modulated by extrinsic nerves. This system with its multiplicity of transmitters and receptors does not always allow a clear interpretation of experimental data, especially with compounds lacking specificity. In this review the complex situation is described particularly in relation to receptor populations (cholinergic, adrenergic, dopamine, histamine, 5-hydroxytryptamine, opioid, gamma-aminobutyric acid (GABA), prostanoid and dihydropyridine receptors), therapeutic aspects of drugs and their usefulness in children. Newer principles with known drugs and promising new compounds with a more appropriate kinetic or fewer side-effects, deriving from distinct pharmacological groups, as candidates for the treatment of gastrointestinal disorders are considered e.g. anticholinergics (prifinium or actilonium bromide), adrenergic alpha 2-agonists (clonidine, lidamidine) for diarrhoea in diabetic neuropathy, adrenergic beta-blockers for shortening postoperative ileus (propranolol), dopamine receptor antagonists (metoclopramide, domperidone, alizapride) and another prokinetic substance (cisapride) which may be useful for a number of applications as gastro-oesophageal reflux, gastro-paresis, intestinal pseudo-obstruction, cystic fibrosis and constipation, morphine derivatives (e.g. loperamide) for intractable diarrhoea and calcium antagonists (e.g. nifedipine) for achalasia. Increasing experience in digestive tract pharmacology and reliable clinical studies will furthermore be the basis for a more specific and better tolerated therapy of gastrointestinal motility disorders in adults and children.

  18. Bacterial Motility Reveals Unknown Molecular Organization.

    PubMed

    Duchesne, Ismaël; Rainville, Simon; Galstian, Tigran

    2015-11-17

    The water solubility of lyotropic liquid crystals (LCs) makes them very attractive to study the behavior of biological microorganisms in an environment where local symmetry is broken (as often encountered in nature). Several recent studies have shown a dramatic change in the behavior of flagellated bacteria when swimming in solutions of the lyotropic LC disodium cromoglycate (DSCG). In this study, the movements of Escherichia coli bacteria in DSCG-water solutions of different concentrations are observed to improve our understanding of this phenomenon. In addition, the viscosity of DSCG aqueous solutions is measured as a function of concentration at room temperature. We also experimentally identify a previously undescribed isotropic pretransition zone where bacteria start sticking to each other and to surfaces. Simple estimations show that the unbalanced osmotic pressure induced depletion force might be responsible for this sticking phenomenon. An estimate of the bacteria propulsive force and the DSCG aggregates length (versus concentration) are calculated from the measured viscosity of the medium. All these quantities are found to undergo a strong increase in the pretransition zone, starting at a threshold concentration of 6±1 wt % DSCG that is well below the known isotropic-LC transition (∼10 wt %). This study also shines light on the motility of flagellated bacteria in realistic environments, and it opens new avenues for interesting applications such as the use of motile microorganisms to probe the physical properties of their host or smart bandages that could guide bacteria out of wounds.

  19. Intrinsic Photosensitivity Enhances Motility of T Lymphocytes

    PubMed Central

    Phan, Thieu X.; Jaruga, Barbara; Pingle, Sandeep C.; Bandyopadhyay, Bidhan C.; Ahern, Gerard P.

    2016-01-01

    Sunlight has important biological effects in human skin. Ultraviolet (UV) light striking the epidermis catalyzes the synthesis of Vitamin D and triggers melanin production. Although a causative element in skin cancers, sunlight is also associated with positive health outcomes including reduced incidences of autoimmune diseases and cancers. The mechanisms, however, by which light affects immune function remain unclear. Here we describe direct photon sensing in human and mouse T lymphocytes, a cell-type highly abundant in skin. Blue light irradiation at low doses (<300 mJ cm−2) triggers synthesis of hydrogen peroxide (H2O2) in T cells revealed by the genetically encoded reporter HyPerRed. In turn, H2O2 activates a Src kinase/phospholipase C-γ1 (PLC-γ1) signaling pathway and Ca2+ mobilization. Pharmacologic inhibition or genetic disruption of Lck kinase, PLC-γ1 or the T cell receptor complex inhibits light-evoked Ca2+ transients. Notably, both light and H2O2 enhance T-cell motility in a Lck-dependent manner. Thus, T lymphocytes possess intrinsic photosensitivity and this property may enhance their motility in skin. PMID:27995987

  20. Major regulatory mechanisms involved in sperm motility.

    PubMed

    Pereira, Rute; Sá, Rosália; Barros, Alberto; Sousa, Mário

    2017-01-01

    The genetic bases and molecular mechanisms involved in the assembly and function of the flagellum components as well as in the regulation of the flagellar movement are not fully understood, especially in humans. There are several causes for sperm immotility, of which some can be avoided and corrected, whereas other are related to genetic defects and deserve full investigation to give a diagnosis to patients. This review was performed after an extensive literature search on the online databases PubMed, ScienceDirect, and Web of Science. Here, we review the involvement of regulatory pathways responsible for sperm motility, indicating possible causes for sperm immotility. These included the calcium pathway, the cAMP-dependent protein kinase pathway, the importance of kinases and phosphatases, the function of reactive oxygen species, and how the regulation of cell volume and osmolarity are also fundamental components. We then discuss main gene defects associated with specific morphological abnormalities. Finally, we slightly discuss some preventive and treatments approaches to avoid development of conditions that are associated with unspecified sperm immotility. We believe that in the near future, with the development of more powerful techniques, the genetic causes of sperm immotility and the regulatory mechanisms of sperm motility will be better understand, thus enabling to perform a full diagnosis and uncover new therapies.

  1. Bacterial Motility Reveals Unknown Molecular Organization

    PubMed Central

    Duchesne, Ismaël; Rainville, Simon; Galstian, Tigran

    2015-01-01

    The water solubility of lyotropic liquid crystals (LCs) makes them very attractive to study the behavior of biological microorganisms in an environment where local symmetry is broken (as often encountered in nature). Several recent studies have shown a dramatic change in the behavior of flagellated bacteria when swimming in solutions of the lyotropic LC disodium cromoglycate (DSCG). In this study, the movements of Escherichia coli bacteria in DSCG-water solutions of different concentrations are observed to improve our understanding of this phenomenon. In addition, the viscosity of DSCG aqueous solutions is measured as a function of concentration at room temperature. We also experimentally identify a previously undescribed isotropic pretransition zone where bacteria start sticking to each other and to surfaces. Simple estimations show that the unbalanced osmotic pressure induced depletion force might be responsible for this sticking phenomenon. An estimate of the bacteria propulsive force and the DSCG aggregates length (versus concentration) are calculated from the measured viscosity of the medium. All these quantities are found to undergo a strong increase in the pretransition zone, starting at a threshold concentration of 6 ± 1 wt % DSCG that is well below the known isotropic-LC transition (∼10 wt %). This study also shines light on the motility of flagellated bacteria in realistic environments, and it opens new avenues for interesting applications such as the use of motile microorganisms to probe the physical properties of their host or smart bandages that could guide bacteria out of wounds. PMID:26588572

  2. Major regulatory mechanisms involved in sperm motility

    PubMed Central

    Pereira, Rute; Sá, Rosália; Barros, Alberto; Sousa, Mário

    2017-01-01

    The genetic bases and molecular mechanisms involved in the assembly and function of the flagellum components as well as in the regulation of the flagellar movement are not fully understood, especially in humans. There are several causes for sperm immotility, of which some can be avoided and corrected, whereas other are related to genetic defects and deserve full investigation to give a diagnosis to patients. This review was performed after an extensive literature search on the online databases PubMed, ScienceDirect, and Web of Science. Here, we review the involvement of regulatory pathways responsible for sperm motility, indicating possible causes for sperm immotility. These included the calcium pathway, the cAMP-dependent protein kinase pathway, the importance of kinases and phosphatases, the function of reactive oxygen species, and how the regulation of cell volume and osmolarity are also fundamental components. We then discuss main gene defects associated with specific morphological abnormalities. Finally, we slightly discuss some preventive and treatments approaches to avoid development of conditions that are associated with unspecified sperm immotility. We believe that in the near future, with the development of more powerful techniques, the genetic causes of sperm immotility and the regulatory mechanisms of sperm motility will be better understand, thus enabling to perform a full diagnosis and uncover new therapies. PMID:26680031

  3. Flagellated bacterial motility in polymer solutions

    PubMed Central

    Martinez, Vincent A.; Schwarz-Linek, Jana; Reufer, Mathias; Wilson, Laurence G.; Morozov, Alexander N.; Poon, Wilson C. K.

    2014-01-01

    It is widely believed that the swimming speed, v, of many flagellated bacteria is a nonmonotonic function of the concentration, c, of high-molecular-weight linear polymers in aqueous solution, showing peaked v(c) curves. Pores in the polymer solution were suggested as the explanation. Quantifying this picture led to a theory that predicted peaked v(c) curves. Using high-throughput methods for characterizing motility, we measured v and the angular frequency of cell body rotation, Ω, of motile Escherichia coli as a function of polymer concentration in polyvinylpyrrolidone (PVP) and Ficoll solutions of different molecular weights. We find that nonmonotonic v(c) curves are typically due to low-molecular-weight impurities. After purification by dialysis, the measured v(c) and Ω(c) relations for all but the highest-molecular-weight PVP can be described in detail by Newtonian hydrodynamics. There is clear evidence for non-Newtonian effects in the highest-molecular-weight PVP solution. Calculations suggest that this is due to the fast-rotating flagella seeing a lower viscosity than the cell body, so that flagella can be seen as nano-rheometers for probing the non-Newtonian behavior of high polymer solutions on a molecular scale. PMID:25468981

  4. Flagellated bacterial motility in polymer solutions.

    PubMed

    Martinez, Vincent A; Schwarz-Linek, Jana; Reufer, Mathias; Wilson, Laurence G; Morozov, Alexander N; Poon, Wilson C K

    2014-12-16

    It is widely believed that the swimming speed, v, of many flagellated bacteria is a nonmonotonic function of the concentration, c, of high-molecular-weight linear polymers in aqueous solution, showing peaked v(c) curves. Pores in the polymer solution were suggested as the explanation. Quantifying this picture led to a theory that predicted peaked v(c) curves. Using high-throughput methods for characterizing motility, we measured v and the angular frequency of cell body rotation, Ω, of motile Escherichia coli as a function of polymer concentration in polyvinylpyrrolidone (PVP) and Ficoll solutions of different molecular weights. We find that nonmonotonic v(c) curves are typically due to low-molecular-weight impurities. After purification by dialysis, the measured v(c) and Ω(c) relations for all but the highest-molecular-weight PVP can be described in detail by Newtonian hydrodynamics. There is clear evidence for non-Newtonian effects in the highest-molecular-weight PVP solution. Calculations suggest that this is due to the fast-rotating flagella seeing a lower viscosity than the cell body, so that flagella can be seen as nano-rheometers for probing the non-Newtonian behavior of high polymer solutions on a molecular scale.

  5. Numerical Simulations of Inclusion Behavior in Gas-Stirred Ladles

    NASA Astrophysics Data System (ADS)

    Lou, Wentao; Zhu, Miaoyong

    2013-06-01

    A computation fluid dynamics-population balance model (CFD-PBM) coupled model has been proposed to investigate the bubbly plume flow and inclusion behavior including growth, size distribution, and removal in gas-stirred ladles, and some new and important phenomena and mechanisms were presented. For the bubbly plume flow, a modified k- ɛ model with extra source terms to account for the bubble-induced turbulence was adopted to model the turbulence, and the bubble turbulent dispersion force was taken into account to predict gas volume fraction distribution in the turbulent gas-stirred system. For inclusion behavior, the phenomena of inclusions turbulent random motion, bubbles wake, and slag eye forming on the molten steel surface were considered. In addition, the multiple mechanisms both that promote inclusion growth due to inclusion-inclusion collision caused by turbulent random motion, shear rate in turbulent eddy, and difference inclusion Stokes velocities, and the mechanisms that promote inclusion removal due to bubble-inclusion turbulence random collision, bubble-inclusion turbulent shear collision, bubble-inclusion buoyancy collision, inclusion own floatation near slag-metal interface, bubble wake capture, and wall adhesion were investigated. The importance of different mechanisms and total inclusion removal ratio under different conditions, and the distribution of inclusion number densities in ladle, were discussed and clarified. The results show that at a low gas flow rate, the inclusion growth is mainly attributed to both turbulent shear collision and Stokes collision, which is notably affected by the Stokes collision efficiency, and the inclusion removal is mainly attributed to the bubble-inclusion buoyancy collision and inclusion own floatation near slag-metal interface. At a higher gas flow rate, the inclusions appear as turbulence random motion in bubbly plume zone, and both the inclusion-inclusion and inclusion-bubble turbulent random collisions become

  6. Cyclic-di-GMP signalling regulates motility and biofilm formation in Bordetella bronchiseptica

    PubMed Central

    Sisti, Federico; Ha, Dae-Gon; O'Toole, George A.; Hozbor, Daniela

    2013-01-01

    The signalling molecule bis-(3′–5′)-cyclic-dimeric guanosine monophosphate (c-di-GMP) is a central regulator of diverse cellular functions, including motility, biofilm formation, cell cycle progression and virulence, in bacteria. Multiple diguanylate cyclase and phosphodiesterase-domain-containing proteins (GGDEF and EAL/HD-GYP, respectively) modulate the levels of the second messenger c-di-GMP to transmit signals and obtain such specific cellular responses. In the genus Bordetella this c-di-GMP network is poorly studied. In this work, we evaluated the expression of two phenotypes in Bordetella bronchiseptica regulated by c-di-GMP, biofilm formation and motility, under the influence of ectopic expression of Pseudomonas aeruginosa proteins with EAL or GGDEF domains that regulates the c-di-GMP level. In agreement with previous reports for other bacteria, we observed that B. bronchiseptica is able to form biofilm and reduce its motility only when GGDEF domain protein is expressed. Moreover we identify a GGDEF domain protein (BB3576) with diguanylate cyclase activity that participates in motility and biofilm regulation in B. bronchiseptica. These results demonstrate for the first time, to our knowledge, the presence of c-di-GMP regulatory signalling in B. bronchiseptica. PMID:23475948

  7. Gene position in a long operon governs motility development in Bacillus subtilis

    PubMed Central

    Cozy, Loralyn M.; Kearns, Daniel B.

    2010-01-01

    Growing cultures of Bacillus subtilis bifurcate into subpopulations of motile individuals and non-motile chains of cells that are differentiated at the level of gene expression. The motile cells are ON and the chaining cells are OFF for transcription that depends on RNA polymerase and the alternative sigma factor σD. Here we show that chaining cells were OFF for σD-dependent gene expression because σD levels fell below a threshold, and σD activity was inhibited by the anti-sigma factor FlgM. The probability that σD exceeded the threshold was governed by the position of the sigD genes. The proportion of ON cells increased when sigD was artificially moved forward in the 27kb fla/che operon. In addition, we identified a new σD-dependent promoter that increases sigD expression and may provide positive feedback to stabilize the ON state. Finally, we demonstrate that ON/OFF motility states in B. subtilis are a form of development because mosaics of stable and differentiated epigenotypes were evident when the normally dispersed bacteria were forced to grow in one dimension. PMID:20233303

  8. Key stages in mammary gland development: the mammary end bud as a motile organ.

    PubMed

    Hinck, Lindsay; Silberstein, Gary B

    2005-01-01

    In the rodent, epithelial end buds define the tips of elongating mammary ducts. These highly motile structures undergo repeated dichotomous branching as they aggressively advance through fatty stroma and, turning to avoid other ducts, they finally cease growth leaving behind the open, tree-like framework on which secretory alveoli develop during pregnancy. This review identifies the motility of end buds as a unique developmental marker that represents the successful integration of systemic and local mammotrophic influences, and covers relevant advances in ductal growth regulation, extracellular matrix (ECM) remodeling, and cell adhesion in the inner end bud. An unexpected growth-promoting synergy between insulin-like growth factor-1 and progesterone, in which ducts elongate without forming new end buds, is described as well as evidence strongly supporting self-inhibition of ductal elongation by end-bud-secreted transforming growth factor-beta acting on stromal targets. The influence of the matrix metalloproteinase ECM-remodeling enzymes, notably matrix metalloproteinase-2, on end bud growth is discussed in the broader context of enzymes that regulate the polysaccharide-rich glycosaminoglycan elements of the ECM. Finally, a critical, motility-enabling role for the cellular architecture of the end bud is identified and the contribution of cadherins, the netrin/neogenin system, and ErbB2 to the structure and motility of end buds is discussed.

  9. An increase or a decrease in myosin II phosphorylation inhibits macrophage motility

    PubMed Central

    1991-01-01

    Myosin II purified from mammalian non-muscle cells is phosphorylated on the 20-kD light chain subunit (MLC20) by the Ca2+/calmodulin-dependent enzyme myosin light chain kinase (MLCK). The importance of MLC20 phosphorylation in regulating cell motility was investigated by introducing either antibodies to MLCK (MK-Ab) or a Ca2+/calmodulin- independent, constitutively active form of MLCK (MK-) into macrophages. The effects of these proteins on cell motility were then determined using a quantitative chemotaxis assay. Chemotaxis is significantly diminished in macrophages containing MK-Ab compared to macrophages containing control antibodies. Moreover, there is an inverse relationship between the number of cells that migrate and the amount of MK-Ab introduced into cells. Interestingly, there is also an inverse relationship between the number of cells that migrate and the amount of MK- introduced into cells. Other experiments demonstrated that MK-Ab decreased intracellular MLC20 phosphorylation while MK- increased MLC20 phosphorylation. MK- also increased the amount of myosin associated with the cytoskeleton. These data demonstrate that the regulation of MLCK is an important aspect of cell motility and suggest that MLC20 phosphorylation must be maintained within narrow limits during translational motility by mammalian cells. PMID:2071674

  10. Bacterial Shape and ActA Distribution Affect Initiation of Listeria monocytogenes Actin-Based Motility

    PubMed Central

    Rafelski, Susanne M.; Theriot, Julie A.

    2005-01-01

    We have examined the process by which the intracellular bacterial pathogen Listeria monocytogenes initiates actin-based motility and determined the contribution of the variable surface distribution of the ActA protein to initiation and steady-state movement. To directly correlate ActA distributions to actin dynamics and motility of live bacteria, ActA was fused to a monomeric red fluorescent protein (mRFP1). Actin comet tail formation and steady-state bacterial movement rates both depended on ActA distribution, which in turn was tightly coupled to the bacterial cell cycle. Motility initiation was found to be a highly complex, multistep process for bacteria, in contrast to the simple symmetry breaking previously observed for ActA-coated spherical beads. F-actin initially accumulated along the sides of the bacterium and then slowly migrated to the bacterial pole expressing the highest density of ActA as a tail formed. Early movement was highly unstable with extreme changes in speed and frequent stops. Over time, saltatory motility and sensitivity to the immediate environment decreased as bacterial movement became robust at a constant steady-state speed. PMID:15980176

  11. Giardia Flagellar Motility Is Not Directly Required to Maintain Attachment to Surfaces

    PubMed Central

    House, Susan A.; Richter, David J.; Pham, Jonathan K.; Dawson, Scott C.

    2011-01-01

    Giardia trophozoites attach to the intestinal microvilli (or inert surfaces) using an undefined “suction-based” mechanism, and remain attached during cell division to avoid peristalsis. Flagellar motility is a key factor in Giardia's pathogenesis and colonization of the host small intestine. Specifically, the beating of the ventral flagella, one of four pairs of motile flagella, has been proposed to generate a hydrodynamic force that results in suction-based attachment via the adjacent ventral disc. We aimed to test this prevailing “hydrodynamic model” of attachment mediated by flagellar motility. We defined four distinct stages of attachment by assessing surface contacts of the trophozoite with the substrate during attachment using TIRF microscopy (TIRFM). The lateral crest of the ventral disc forms a continuous perimeter seal with the substrate, a cytological indication that trophozoites are fully attached. Using trophozoites with two types of molecularly engineered defects in flagellar beating, we determined that neither ventral flagellar beating, nor any flagellar beating, is necessary for the maintenance of attachment. Following a morpholino-based knockdown of PF16, a central pair protein, both the beating and morphology of flagella were defective, but trophozoites could still initiate proper surface contacts as seen using TIRFM and could maintain attachment in several biophysical assays. Trophozoites with impaired motility were able to attach as well as motile cells. We also generated a strain with defects in the ventral flagellar waveform by overexpressing a dominant negative form of alpha2-annexin::GFP (D122A, D275A). This dominant negative alpha2-annexin strain could initiate attachment and had only a slight decrease in the ability to withstand normal and shear forces. The time needed for attachment did increase in trophozoites with overall defective flagellar beating, however. Thus while not directly required for attachment, flagellar motility is

  12. Balancing Thymocyte Adhesion and Motility: A Functional Linkage Between β1 Lntegrins and The Motility Receptor RHAMM

    PubMed Central

    Gares, Sheryl L.

    2000-01-01

    Thymocyte differentiation involves several processes that occur in different anatomic sites within the thymus. Therefore, thymocytes must have the ability to respond to signals received from stromal cells and adopt either adhesive or motile behavior. We will discuss our data indicating human thymocytes use α4β1 integrin, α5β1 integrin and RHAMM to mediate these activities. Immature multinegative (MN; CD3–4–8–19-) thymocytes use α4β1 and α5β1 integrins to mediate weak and strong adhesion. This subset also uses α4β1 integrin to mediate motility. As thymocytes differentiate, they begin to express and use RHAMM to mediate motility in conjunction with α4β1 and α5β1 integrins. Motile thymocytes use β1 integrins to maintain weakly adhesive contacts with substrate to provide traction for locomoting cells, thus weak adhesion is a requirement of motile behavior. Hyaluronan (HA) is also required by thymocytes to mediate motility. HA binding to cell surface RHAMM redistributes intracellular RHAMM to the cell surface where it functions to mediate motility. We propose that the decision to maintain adhesive or motile behavior is based on the balance between low and high avidity binding conformations of β1 integrins on thymocytes and that RHAMM:HA interactions decrease high avidity binding conformations of integrins pushing the balance toward motile behavior. PMID:11097213

  13. Paxillin mediates sensing of physical cues and regulates directional cell motility by controlling lamellipodia positioning.

    PubMed

    Sero, Julia E; Thodeti, Charles K; Mammoto, Akiko; Bakal, Chris; Thomas, Sheila; Ingber, Donald E

    2011-01-01

    Physical interactions between cells and the extracellular matrix (ECM) guide directional migration by spatially controlling where cells form focal adhesions (FAs), which in turn regulate the extension of motile processes. Here we show that physical control of directional migration requires the FA scaffold protein paxillin. Using single-cell sized ECM islands to constrain cell shape, we found that fibroblasts cultured on square islands preferentially activated Rac and extended lamellipodia from corner, rather than side regions after 30 min stimulation with PDGF, but that cells lacking paxillin failed to restrict Rac activity to corners and formed small lamellipodia along their entire peripheries. This spatial preference was preceded by non-spatially constrained formation of both dorsal and lateral membrane ruffles from 5-10 min. Expression of paxillin N-terminal (paxN) or C-terminal (paxC) truncation mutants produced opposite, but complementary, effects on lamellipodia formation. Surprisingly, pax-/- and paxN cells also formed more circular dorsal ruffles (CDRs) than pax+ cells, while paxC cells formed fewer CDRs and extended larger lamellipodia even in the absence of PDGF. In a two-dimensional (2D) wound assay, pax-/- cells migrated at similar speeds to controls but lost directional persistence. Directional motility was rescued by expressing full-length paxillin or the N-terminus alone, but paxN cells migrated more slowly. In contrast, pax-/- and paxN cells exhibited increased migration in a three-dimensional (3D) invasion assay, with paxN cells invading Matrigel even in the absence of PDGF. These studies indicate that paxillin integrates physical and chemical motility signals by spatially constraining where cells will form motile processes, and thereby regulates directional migration both in 2D and 3D. These findings also suggest that CDRs may correspond to invasive protrusions that drive cell migration through 3D extracellular matrices.

  14. The interplay between cell motility and tissue architecture

    NASA Astrophysics Data System (ADS)

    Tanner, Kandice

    2013-03-01

    Glandular tissue form arboreal networks comprised of acini and tubes. Loss of structure is concomitant with the in vivo pathologic state. In vitro models have been shown to recapitulate the functional units of the mammary gland and other organs. Despite our much improved understanding gleaned from both in vitro and in vivo interrogation, the mechanisms by which cells are able to achieve the correct tissue organization remain elusive. How do single mammary epithelial cells form polarized acini when cultured in a surrogate basement membrane gel but not on 2D surfaces? Simply put, how does a cell know which way is up? Why do malignant breast cells show a differential response in that they form non-polarized aggregates? Recently, it was determined that non-malignant cells undergo multiple rotations to establish acini while tumor cells are randomly motile during tumor formation. Can it be that a tumor cell has simply lost its way. This research was supported by the Intramural Research Program of the NIH, National Cancer Institute.

  15. A Glycosylation Mutant of Trypanosoma brucei Links Social Motility Defects In Vitro to Impaired Colonization of Tsetse Flies In Vivo.

    PubMed

    Imhof, Simon; Vu, Xuan Lan; Bütikofer, Peter; Roditi, Isabel

    2015-06-01

    Transmission of African trypanosomes by tsetse flies requires that the parasites migrate out of the midgut lumen and colonize the ectoperitrophic space. Early procyclic culture forms correspond to trypanosomes in the lumen; on agarose plates they exhibit social motility, migrating en masse as radial projections from an inoculation site. We show that an Rft1(-/-) mutant needs to reach a greater threshold number before migration begins, and that it forms fewer projections than its wild-type parent. The mutant is also up to 4 times less efficient at establishing midgut infections. Ectopic expression of Rft1 rescues social motility defects and restores the ability to colonize the fly. These results are consistent with social motility reflecting movement to the ectoperitrophic space, implicate N-glycans in the signaling cascades for migration in vivo and in vitro, and provide the first evidence that parasite-parasite interactions determine the success of transmission by the insect host.

  16. Bacterial motility and chemotaxis in shear

    NASA Astrophysics Data System (ADS)

    Rusconi, Roberto; Guasto, Jeffrey S.; Son, Kwangmin; Stocker, Roman

    2011-11-01

    Bacteria often exhibit directed motility (``taxis'') in response to gradients of dissolved resources, like nutrients or oxygen. While we have a detailed understanding of chemotaxis in quiescent environments, it has been largely overlooked how this behavior is affected by fluid flow, despite the ubiquity of flow in bacterial habitats. Here we present experiments on aerotaxis (attraction to dissolved oxygen) of Bacillus subtilis in controlled shear flows. Using novel microfluidic devices we expose bacterial suspensions to steady oxygen gradients, with independent control over shear rates. From single-cell trajectories and the spatial distribution of bacteria, we show that the cell rotation induced by shear reduces the aerotactic performance, demonstrating that hydrodynamic conditions affect bacterial fitness.

  17. Quantum-dot-based cell motility assay.

    PubMed

    Gu, Weiwei; Pellegrino, Teresa; Parak, Wolfgang J; Boudreau, Rosanne; Le Gros, Mark A; Gerion, Daniele; Alivisatos, A Paul; Larabell, Carolyn A

    2005-06-28

    Because of their favorable physical and photochemical properties, colloidal CdSe/ZnS-semiconductor nanocrystals (commonly known as quantum dots) have enormous potential for use in biological imaging. In this report, we present an assay that uses quantum dots as markers to quantify cell motility. Cells that are seeded onto a homogeneous layer of quantum dots engulf and absorb the nanocrystals and, as a consequence, leave behind a fluorescence-free trail. By subsequently determining the ratio of cell area to fluorescence-free track area, we show that it is possible to differentiate between invasive and noninvasive cancer cells. Because this assay uses simple fluorescence detection, requires no significant data processing, and can be used in live-cell studies, it has the potential to be a powerful new tool for discriminating between invasive and noninvasive cancer cell lines or for studying cell signaling events involved in migration.

  18. Spontaneous Motility of Actin Lamellar Fragments

    NASA Astrophysics Data System (ADS)

    Blanch-Mercader, C.; Casademunt, J.

    2013-02-01

    We show that actin lamellar fragments driven solely by polymerization forces at the bounding membrane are generically motile when the circular symmetry is spontaneously broken, with no need of molecular motors or global polarization. We base our study on a nonlinear analysis of a recently introduced minimal model [Callan-Jones et al., Phys. Rev. Lett. 100, 258106 (2008)PRLTAO0031-900710.1103/PhysRevLett.100.258106]. We prove the nonlinear instability of the center of mass and find an exact and simple relation between shape and center-of-mass velocity. A complex subcritical bifurcation scenario into traveling solutions is unfolded, where finite velocities appear through a nonadiabatic mechanism. Examples of traveling solutions and their stability are studied numerically.

  19. Polymer confinement and bacterial gliding motility

    NASA Astrophysics Data System (ADS)

    Jeon, J.; Dobrynin, A. V.

    2005-07-01

    Cyanobacteria and myxobacteria use slime secretion for gliding motility over surfaces. The slime is produced by the nozzle-like pores located on the bacteria surface. To understand the mechanism of gliding motion and its relation to slime polymerization, we have performed molecular dynamics simulations of a molecular nozzle with growing inside polymer chains. These simulations show that the compression of polymer chains inside the nozzle is a driving force for propulsion. There is a linear relationship between the average nozzle velocity and the chain polymerization rate with a proportionality coefficient dependent on the geometric characteristics of the nozzle such as its length and friction coefficient. This minimal model of the molecular engine was used to explain the gliding motion of bacteria over surfaces.

  20. Method and system for enhancing microbial motility

    SciTech Connect

    Hazen, T.C.; Lopez-De-Victoria, G.

    1992-12-31

    A method and system for enhancing the motility of microorganisms by placing an effective amount of chlorinated hydrocarbons, preferably chlorinated alkenes, and most preferably trichloroethylene in spaced relation to the microbes so that the surprisingly strong, monomodal, chemotactic response of the chlorinated hydrocarbon on subsurface microbes can draw the microbes away from or towards and into a substance, as desired. In remediation of groundwater pollution, for example, TCE can be injected into the plume to increase the population of microbes at the plume whereby the plume can be more quickly degraded. A TCE-degrading microbe, such as Welchia alkenophilia, can be used to degrade the TCE following the degradation of the original pollutant.

  1. Method and system for enhancing microbial motility

    SciTech Connect

    Hazen, T.C.; Lopez-De-Victoria, G.

    1990-01-05

    A method and system for enhancing the motility of microorganisms by placing an effective amount of chlorinated hydrocarbons, preferably chlorinated alkenes, and most preferably trichloroethylene in spaced relation to the microbes so that the surprisingly strong, monomodal, chemotactic response of the chlorinated hydrocarbon on subsurface microbes can draw the microbes away from or towards and into a substance, as desired. In remediation of groundwater pollution, for example, TCE can be injected into the plume to increase the population of microbes at the plume whereby the plume can be more quickly degraded. A TCE-degrading microbe, such as Welchia alkenophilia, can be used to degrade the TCE following the degradation of the original pollutant. 5 figs.

  2. Quantification of motility of carabid beetles in farmland.

    PubMed

    Allema, A B; van der Werf, W; Groot, J C J; Hemerik, L; Gort, G; Rossing, W A H; van Lenteren, J C

    2015-04-01

    Quantification of the movement of insects at field and landscape levels helps us to understand their ecology and ecological functions. We conducted a meta-analysis on movement of carabid beetles (Coleoptera: Carabidae), to identify key factors affecting movement and population redistribution. We characterize the rate of redistribution using motility μ (L2 T-1), which is a measure for diffusion of a population in space and time that is consistent with ecological diffusion theory and which can be used for upscaling short-term data to longer time frames. Formulas are provided to calculate motility from literature data on movement distances. A field experiment was conducted to measure the redistribution of mass-released carabid, Pterostichus melanarius in a crop field, and derive motility by fitting a Fokker-Planck diffusion model using inverse modelling. Bias in estimates of motility from literature data is elucidated using the data from the field experiment as a case study. The meta-analysis showed that motility is 5.6 times as high in farmland as in woody habitat. Species associated with forested habitats had greater motility than species associated with open field habitats, both in arable land and woody habitat. The meta-analysis did not identify consistent differences in motility at the species level, or between clusters of larger and smaller beetles. The results presented here provide a basis for calculating time-varying distribution patterns of carabids in farmland and woody habitat. The formulas for calculating motility can be used for other taxa.

  3. Laser radiation and motility patterns of human sperm

    SciTech Connect

    Lenzi, A.; Claroni, F.; Gandini, L.; Lombardo, F.; Barbieri, C.; Lino, A.; Dondero, F. )

    1989-01-01

    Human sperm were exposed in vitro to laser radiation. An increase in progressive sperm motility was associated with a faster rate of sperm ATP consumption. Computer-assisted analysis of sperm motility confirmed the positive effect of laser irradiation on velocity and linearity of sperm.

  4. Detection and Genomic Characterization of Motility in Lactobacillus curvatus: Confirmation of Motility in a Species outside the Lactobacillus salivarius Clade

    PubMed Central

    Cousin, Fabien J.; Lynch, Shónagh M.; Harris, Hugh M. B.; McCann, Angela; Lynch, Denise B.; Neville, B. Anne; Irisawa, Tomohiro; Okada, Sanae; Endo, Akihito

    2014-01-01

    Lactobacillus is the largest genus within the lactic acid bacteria (LAB), with almost 180 species currently identified. Motility has been reported for at least 13 Lactobacillus species, all belonging to the Lactobacillus salivarius clade. Motility in lactobacilli is poorly characterized. It probably confers competitive advantages, such as superior nutrient acquisition and niche colonization, but it could also play an important role in innate immune system activation through flagellin–Toll-like receptor 5 (TLR5) interaction. We now report strong evidence of motility in a species outside the L. salivarius clade, Lactobacillus curvatus (strain NRIC 0822). The motility of L. curvatus NRIC 0822 was revealed by phase-contrast microscopy and soft-agar motility assays. Strain NRIC 0822 was motile at temperatures between 15°C and 37°C, with a range of different carbohydrates, and under varying atmospheric conditions. We sequenced the L. curvatus NRIC 0822 genome, which revealed that the motility genes are organized in a single operon and that the products are very similar (>98.5% amino acid similarity over >11,000 amino acids) to those encoded by the motility operon of Lactobacillus acidipiscis KCTC 13900 (shown for the first time to be motile also). Moreover, the presence of a large number of mobile genetic elements within and flanking the motility operon of L. curvatus suggests recent horizontal transfer between members of two distinct Lactobacillus clades: L. acidipiscis in the L. salivarius clade and L. curvatus in the L. sakei clade. This study provides novel phenotypic, genetic, and phylogenetic insights into flagellum-mediated motility in lactobacilli. PMID:25501479

  5. Detection and genomic characterization of motility in Lactobacillus curvatus: confirmation of motility in a species outside the Lactobacillus salivarius clade.

    PubMed

    Cousin, Fabien J; Lynch, Shónagh M; Harris, Hugh M B; McCann, Angela; Lynch, Denise B; Neville, B Anne; Irisawa, Tomohiro; Okada, Sanae; Endo, Akihito; O'Toole, Paul W

    2015-02-01

    Lactobacillus is the largest genus within the lactic acid bacteria (LAB), with almost 180 species currently identified. Motility has been reported for at least 13 Lactobacillus species, all belonging to the Lactobacillus salivarius clade. Motility in lactobacilli is poorly characterized. It probably confers competitive advantages, such as superior nutrient acquisition and niche colonization, but it could also play an important role in innate immune system activation through flagellin–Toll-like receptor 5 (TLR5) interaction. We now report strong evidence of motility in a species outside the L. salivarius clade, Lactobacillus curvatus (strain NRIC0822). The motility of L. curvatus NRIC 0822 was revealed by phase-contrast microscopy and soft-agar motility assays. Strain NRIC 0822 was motile at temperatures between 15 °C and 37 °C, with a range of different carbohydrates, and under varying atmospheric conditions. We sequenced the L. curvatus NRIC 0822 genome, which revealed that the motility genes are organized in a single operon and that the products are very similar (>98.5% amino acid similarity over >11,000 amino acids) to those encoded by the motility operon of Lactobacillus acidipiscis KCTC 13900 (shown for the first time to be motile also). Moreover, the presence of a large number of mobile genetic elements within and flanking the motility operon of L. curvatus suggests recent horizontal transfer between members of two distinct Lactobacillus clades: L. acidipiscis in the L. salivarius clade and L. curvatus inthe L. sakei clade. This study provides novel phenotypic, genetic, and phylogenetic insights into flagellum-mediated motility in lactobacilli.

  6. Kinematic analysis of Toxoplasma gondii motility.

    PubMed

    Frixione, E; Mondragón, R; Meza, I

    1996-01-01

    Toxoplasma gondii tachyzoites execute a complex and little understood combination of rapid movements to reach and penetrate human or other animals cells. In the present study, computer-assisted simulation was used to quantitatively analyze the motility of these parasites in three-dimensional space with spatial and temporal resolutions in the micrometer and subsecond ranges. A digital model based on electron-micrographs of a serially sectioned tachyzoite was animated according to a videomicrographed sequence of a characteristic repetitive movement. Keyframe animation defined over 150 frames by a total of 36 kinematic parameters for specific motions, of both the whole model and particular domains, resulted in a real-time life-like simulation of the videorecorded tachyzoite movement. The kinematic values indicate that a full revolution of the model is composed of three half-turns accomplished in nearly 5 s with two phases: a relatively slow 180 degrees tilting with regard to the substratum plane, followed by fast (over 200 degrees/s) spinning almost simultaneous with pivoting around the posterior end, each clockwise and for about 180 degrees. Maximal flexing of the body, as well as bowing and retraction of its anterior end, occur at midway during the tilting phase. An estimated 70 degrees. clockwise torsion of the body seems to precede the spinning-pivoting phase. The results suggest the operation of two basic forces in the motility of T. gondii tachyzoites: (1) a clockwise torque that causes torsion, spinning, and pivoting; and (2) a longitudinal pull that contracts, bends and tilts the parasite. We discuss the possibility that both of these forces might result from the action of an actin-myosin system enveloping the twisted framework of microtubules characteristic of these organisms.

  7. Thyroxin Is Useful to Improve Sperm Motility

    PubMed Central

    Mendeluk, Gabriela Ruth; Rosales, Mónica

    2016-01-01

    Background The aim of this study was to evaluate the non-genomic action of thyroxin on sperm kinetic and its probable use to improve sperm recovery after applying an en- richment method like “swim-up” in comparison with the available one, pentoxifylline. Materials and Methods This is an experimental study. A total of 50 patients were re- cruited, followed by infertility consultation. Conventional sperm assays were performed according to World Health Organization criteria-2010 (WHO-2010). A Computer Aided Semen Analysis System was employed to assess kinetic parameters and concentrations. Number of the motile sperm recovered after preparation technique was calculated. Results Addition of T4 (0.002 µg/ml) to semen samples increased hypermotility at 20 minutes (control: 14.18 ± 5.1% vs. 17.66 ± 8.88%, P<0.03, data expressed as mean ± SD) and remained unchanged after 40 minutes. Significant differences were found in the motile sperm recovered after swim-up (control: 8.93×106 ± 9.52× 06vs. 17.20×106 ± 21.16×106, P<0.03), achieving all of the tested samples a desirable threshold value for artificial insemination outcome, while adding pentoxifylline increased the number of recovered sperm after swim-up in 60% of the studied cases. No synergism between two treatments could be determined. Conclusion We propose a new physiological tool to artificially improve insemination. The discussion opens windows to investigate unknown pathways involved in sperm ca- pacitation and gives innovative arguments to better understand infertility mechanisms. PMID:27441054

  8. Gliding Motility Revisited: How Do the Myxobacteria Move without Flagella?

    PubMed Central

    Mauriello, Emilia M. F.; Mignot, Tâm; Yang, Zhaomin; Zusman, David R.

    2010-01-01

    Summary: In bacteria, motility is important for a wide variety of biological functions such as virulence, fruiting body formation, and biofilm formation. While most bacteria move by using specialized appendages, usually external or periplasmic flagella, some bacteria use other mechanisms for their movements that are less well characterized. These mechanisms do not always exhibit obvious motility structures. Myxococcus xanthus is a motile bacterium that does not produce flagella but glides slowly over solid surfaces. How M. xanthus moves has remained a puzzle that has challenged microbiologists for over 50 years. Fortunately, recent advances in the analysis of motility mutants, bioinformatics, and protein localization have revealed likely mechanisms for the two M. xanthus motility systems. These results are summarized in this review. PMID:20508248

  9. Analysis of energy sources for Mycoplasma penetrans gliding motility.

    PubMed

    Jurkovic, Dominika A; Hughes, Michael R; Balish, Mitchell F

    2013-01-01

    Mycoplasma penetrans, a potential human pathogen found mainly in HIV-infected individuals, uses a tip structure for both adherence and gliding motility. To improve our understanding of the molecular mechanism of M. penetrans gliding motility, we used chemical inhibitors of energy sources associated with motility of other organisms to determine which of these is used by M. penetrans and also tested whether gliding speed responded to temperature and pH. Mycoplasma penetrans gliding motility was not eliminated in the presence of a proton motive force inhibitor, a sodium motive force inhibitor, or an agent that depletes cellular ATP. At near-neutral pH, gliding speed increased as temperature increased. The absence of a clear chemical energy source for gliding motility and a positive correlation between speed and temperature suggest that energy derived from heat provides the major source of power for the gliding motor of M. penetrans.

  10. Motile axonal mitochondria contribute to the variability of presynaptic strength.

    PubMed

    Sun, Tao; Qiao, Haifa; Pan, Ping-Yue; Chen, Yanmin; Sheng, Zu-Hang

    2013-08-15

    One of the most notable characteristics of synaptic transmission is the wide variation in synaptic strength in response to identical stimulation. In hippocampal neurons, approximately one-third of axonal mitochondria are highly motile, and some dynamically pass through presynaptic boutons. This raises a fundamental question: can motile mitochondria contribute to the pulse-to-pulse variability of presynaptic strength? Recently, we identified syntaphilin as an axonal mitochondrial-docking protein. Using hippocampal neurons and slices of syntaphilin knockout mice, we demonstrate that the motility of axonal mitochondria correlates with presynaptic variability. Enhancing mitochondrial motility increases the pulse-to-pulse variability, whereas immobilizing mitochondria reduces the variability. By dual-color live imaging at single-bouton levels, we further show that motile mitochondria passing through boutons dynamically influence synaptic vesicle release, mainly by altering ATP homeostasis in axons. Thus, our study provides insight into the fundamental properties of the CNS to ensure the plasticity and reliability of synaptic transmission.

  11. Computational approaches to substrate-based cell motility

    NASA Astrophysics Data System (ADS)

    Ziebert, Falko; Aranson, Igor S.

    2016-07-01

    Substrate-based crawling motility of eukaryotic cells is essential for many biological functions, both in developing and mature organisms. Motility dysfunctions are involved in several life-threatening pathologies such as cancer and metastasis. Motile cells are also a natural realisation of active, self-propelled 'particles', a popular research topic in nonequilibrium physics. Finally, from the materials perspective, assemblies of motile cells and evolving tissues constitute a class of adaptive self-healing materials that respond to the topography, elasticity and surface chemistry of the environment and react to external stimuli. Although a comprehensive understanding of substrate-based cell motility remains elusive, progress has been achieved recently in its modelling on the whole-cell level. Here we survey the most recent advances in computational approaches to cell movement and demonstrate how these models improve our understanding of complex self-organised systems such as living cells.

  12. A mechanism for cell motility by active polar gels

    PubMed Central

    Marth, W.; Praetorius, S.; Voigt, A.

    2015-01-01

    We analyse a generic motility model, with the motility mechanism arising by contractile stress due to the interaction of myosin and actin. A hydrodynamic active polar gel theory is used to model the cytoplasm of a cell and is combined with a Helfrich-type model to account for membrane properties. The overall model allows consideration of the motility without the necessity for local adhesion. Besides a detailed numerical approach together with convergence studies for the highly nonlinear free boundary problem, we also compare the induced flow field of the motile cell with that of classical squirmer models and identify the motile cell as a puller or pusher, depending on the strength of the myosin–actin interactions. PMID:25926698

  13. Esophageal motility in nonacid reflux compared with acid reflux.

    PubMed

    Wang, Victor S; Feldman, Natan; Maurer, Rie; Burakoff, Robert

    2009-09-01

    Esophageal motility has been well studied in gastroesophageal reflux disease (GERD) and acid reflux, but not in nonacid reflux. Consecutive patients who had both 24-h multichannel intraluminal impedance-pH (MII-pH) and esophageal motility tests for suspected GERD were studied. Patients were grouped into nonacid refluxers, acid refluxers, and nonrefluxers based on positive symptom correlation and objective findings of acid reflux. Of 96 patients enrolled, 21 patients (22%) were nonacid refluxers, 44 patients (46%) were acid refluxers, and 31 patients (32%) had no objective evidence of reflux. Normal motility was recorded in 86% of nonacid refluxers, 71% of acid refluxers, and 60% of nonrefluxers. Ineffective esophageal motility was seen in 24% of acid refluxers, and 5% of nonacid refluxers (P = 0.11). Symptomatic nonacid reflux events comprised 22% of patients studied for GERD symptoms by MII-pH. Esophageal motility in nonacid reflux is normal 86% of the time.

  14. A random cell motility gradient downstream of FGF controls elongation of an amniote embryo

    PubMed Central

    Bénazéraf, Bertrand; Francois, Paul; Baker, Ruth E.; Denans, Nicolas; Little, Charles D.; Pourquie, Olivier

    2011-01-01

    Vertebrate embryos are characterized by an elongated antero-posterior (AP) body axis, which forms by progressive cell deposition from a posterior growth zone in the embryo. Here, we used tissue ablation in the chicken embryo to demonstrate that the caudal presomitic mesoderm (PSM) plays a key role in axis elongation. Using time-lapse microscopy, we analysed the movements of fluorescently labelled cells in the PSM during embryo elongation which revealed a clear posterior-to-anterior gradient of cell motility and directionality in the PSM. We tracked the movement of the PSM extracellular matrix in parallel with the labelled cells and subtracted the extracellular matrix movement from the global motion of cells. After subtraction, cell motility remained graded but lacked directionality, indicating that the posterior cell movements associated with axis elongation in the PSM are not intrinsic but reflect tissue deformation. The gradient of cell motion along the PSM parallels the fibroblast growth factor (FGF)/mitogen-activated protein kinase (MAPK) gradient 1, which has been implicated in the control of cell motility in this tissue2. Both FGF signalling gain- and loss-of-function experiments lead to disruption of the motility gradient and a slowing down of axis elongation. Furthermore, embryos treated with cell movement inhibitors (Blebbistatin or RhoK inhibitor), but not cell cycle inhibitors, show a slower axis elongation rate. We propose that the gradient of random cell motility downstream of FGF signalling in the PSM controls posterior elongation in the amniote embryo. Our data suggest that tissue elongation is an emergent property that arises from the collective regulation of graded, random cell motion rather than by the regulation of directionality of individual cellular movements. PMID:20613841

  15. High motility reduces grazing mortality of planktonic bacteria.

    PubMed

    Matz, Carsten; Jürgens, Klaus

    2005-02-01

    We tested the impact of bacterial swimming speed on the survival of planktonic bacteria in the presence of protozoan grazers. Grazing experiments with three common bacterivorous nanoflagellates revealed low clearance rates for highly motile bacteria. High-resolution video microscopy demonstrated that the number of predator-prey contacts increased with bacterial swimming speed, but ingestion rates dropped at speeds of >25 microm s(-1) as a result of handling problems with highly motile cells. Comparative studies of a moderately motile strain (<25 microm s(-1)) and a highly motile strain (>45 microm s(-1)) further revealed changes in the bacterial swimming speed distribution due to speed-selective flagellate grazing. Better long-term survival of the highly motile strain was indicated by fourfold-higher bacterial numbers in the presence of grazing compared to the moderately motile strain. Putative constraints of maintaining high swimming speeds were tested at high growth rates and under starvation with the following results: (i) for two out of three strains increased growth rate resulted in larger and slower bacterial cells, and (ii) starved cells became smaller but maintained their swimming speeds. Combined data sets for bacterial swimming speed and cell size revealed highest grazing losses for moderately motile bacteria with a cell size between 0.2 and 0.4 microm(3). Grazing mortality was lowest for cells of >0.5 microm(3) and small, highly motile bacteria. Survival efficiencies of >95% for the ultramicrobacterial isolate CP-1 (< or =0.1 microm(3), >50 microm s(-1)) illustrated the combined protective action of small cell size and high motility. Our findings suggest that motility has an important adaptive function in the survival of planktonic bacteria during protozoan grazing.

  16. Ineffective esophageal motility (IEM): the primary finding in patients with nonspecific esophageal motility disorder.

    PubMed

    Leite, L P; Johnston, B T; Barrett, J; Castell, J A; Castell, D O

    1997-09-01

    Nonspecific esophageal motility disorder (NEMD) is a vague category used to include patients with poorly defined esophageal contraction abnormalities. The criteria include "ineffective" contraction waves, ie, peristaltic waves that are either of low amplitude or are not transmitted. The aim of this study was to identify the prevalence of ineffective esophageal motility (IEM) found during manometry testing and to evaluate esophageal acid exposure and esophageal acid clearance (EAC) in patients with IEM compared to those with other motility findings. We analyzed esophageal manometric tracings from 600 consecutive patients undergoing manometry in our laboratory following a specific protocol from April 1992 through October 1994 to identify the frequency of ineffective contractions and the percentages of other motility abnormalities present in patients meeting criteria for NEMD. Comparison of acid exposure and EAC was made with 150 patients who also had both esophageal manometry and pH-metry over the same time period. Sixty-one of 600 patients (10%) met the diagnostic criteria for NEMD. Sixty of 61 (98%) of these patients had IEM, defined by at least 30% ineffective contractions out of 10 wet swallows. Thirty-five of these patients also underwent ambulatory esophageal pH monitoring. Patients with IEM demonstrated significant increases in both recumbent median percentage of time of pH <4 (4.5%) and median distal EAC (4.2 min/episode) compared to those with normal motility (0.2%, 1 min/episode), diffuse esophageal spasm (0%, 0.6 min/episode), hypertensive LES (0%, 1.8 min/episode), and nutcracker esophagus (0.4% 1.6 min/episode). Recumbent acid exposure in IEM did not differ significantly from that in patients with systemic scleroderma (SSc) for either variable (5.4%, 4.2 min/episode). We propose that IEM is a more appropriate term and should replace NEMD, giving it a more specific manometric identity. IEM patients demonstrate a distinctive recumbent reflux pattern

  17. Novel ultrastructures of Treponema primitia and their implications for motility

    PubMed Central

    Murphy, Gavin E.; Matson, Eric G.; Leadbetter, Jared R.; Berg, Howard C.; Jensen, Grant J.

    2011-01-01

    Summary Members of the bacterial phylum Spirochaetes are generally helical cells propelled by periplasmic flagella. The spirochete Treponema primitia is interesting because of its mutualistic role in the termite gut, where it is believed to cooperate with protozoa that break down cellulose and produce H2 as a by-product. Here we report the ultrastructure of T. primitia as obtained by electron cryotomography of intact, frozen-hydrated cells. Several previously unrecognized external structures were revealed, including bowl-like objects decorating the outer membrane, arcades of hook-shaped proteins winding along the exterior and tufts of fibrils extending from the cell tips. Inside the periplasm, cone-like structures were found at each pole. Instead of the single peptidoglycan layer typical of other Gram-negative bacteria, two distinct periplasmic layers were observed. These layers formed a central open space that contained two flagella situated adjacent to each other. In some areas, the inner membrane formed flattened invaginations that protruded into the cytoplasm. High-speed light microscopic images of swimming T. primitia cells showed that cell bodies remained rigid and moved in a helical rather than planar motion. Together, these findings support the ‘rolling cylinder’ model for T. primitia motility that posits rotation of the protoplasmic cylinder within the outer sheath. PMID:18248579

  18. Exosome secretion affects social motility in Trypanosoma brucei

    PubMed Central

    Shaked, Hadassa; Arvatz, Gil; Tkacz, Itai Dov; Binder, Lior; Waldman Ben-Asher, Hiba; Okalang, Uthman; Chikne, Vaibhav; Cohen-Chalamish, Smadar; Michaeli, Shulamit

    2017-01-01

    Extracellular vesicles (EV) secreted by pathogens function in a variety of biological processes. Here, we demonstrate that in the protozoan parasite Trypanosoma brucei, exosome secretion is induced by stress that affects trans-splicing. Following perturbations in biogenesis of spliced leader RNA, which donates its spliced leader (SL) exon to all mRNAs, or after heat-shock, the SL RNA is exported to the cytoplasm and forms distinct granules, which are then secreted by exosomes. The exosomes are formed in multivesicular bodies (MVB) utilizing the endosomal sorting complexes required for transport (ESCRT), through a mechanism similar to microRNA secretion in mammalian cells. Silencing of the ESCRT factor, Vps36, compromised exosome secretion but not the secretion of vesicles derived from nanotubes. The exosomes enter recipient trypanosome cells. Time-lapse microscopy demonstrated that cells secreting exosomes or purified intact exosomes affect social motility (SoMo). This study demonstrates that exosomes are delivered to trypanosome cells and can change their migration. Exosomes are used to transmit stress signals for communication between parasites. PMID:28257521

  19. Cooperative cell motility during tandem locomotion of amoeboid cells

    PubMed Central

    Bastounis, Effie; Álvarez-González, Begoña; del Álamo, Juan C.; Lasheras, Juan C.; Firtel, Richard A.

    2016-01-01

    Streams of migratory cells are initiated by the formation of tandem pairs of cells connected head to tail to which other cells subsequently adhere. The mechanisms regulating the transition from single to streaming cell migration remain elusive, although several molecules have been suggested to be involved. In this work, we investigate the mechanics of the locomotion of Dictyostelium tandem pairs by analyzing the spatiotemporal evolution of their traction adhesions (TAs). We find that in migrating wild-type tandem pairs, each cell exerts traction forces on stationary sites (∼80% of the time), and the trailing cell reuses the location of the TAs of the leading cell. Both leading and trailing cells form contractile dipoles and synchronize the formation of new frontal TAs with ∼54-s time delay. Cells not expressing the lectin discoidin I or moving on discoidin I–coated substrata form fewer tandems, but the trailing cell still reuses the locations of the TAs of the leading cell, suggesting that discoidin I is not responsible for a possible chemically driven synchronization process. The migration dynamics of the tandems indicate that their TAs’ reuse results from the mechanical synchronization of the leading and trailing cells’ protrusions and retractions (motility cycles) aided by the cell–cell adhesions. PMID:26912787

  20. AMP-activated kinase in human spermatozoa: identification, intracellular localization, and key function in the regulation of sperm motility.

    PubMed

    Calle-Guisado, Violeta; de Llera, Ana Hurtado; Martin-Hidalgo, David; Mijares, Jose; Gil, Maria C; Alvarez, Ignacio S; Bragado, Maria J; Garcia-Marin, Luis J

    2016-09-27

    AMP-activated kinase (AMPK), a protein that regulates energy balance and metabolism, has recently been identified in boar spermatozoa where regulates key functional sperm processes essential for fertilization. This work's aims are AMPK identification, intracellular localization, and their role in human spermatozoa function. Semen was obtained from healthy human donors. Sperm AMPK and phospho-Thr172-AMPK were analyzed by Western blotting and indirect immunofluorescence. High- and low-quality sperm populations were separated by a 40%-80% density gradient. Human spermatozoa motility was evaluated by an Integrated Semen Analysis System (ISAS) in the presence or absence of the AMPK inhibitor compound C (CC). AMPK is localized along the human spermatozoa, at the entire acrosome, midpiece and tail with variable intensity, whereas its active form, phospho-Thr172-AMPK, shows a prominent staining at the acrosome and sperm tail with a weaker staining in the midpiece and the postacrosomal region. Interestingly, spermatozoa bearing an excess residual cytoplasm show strong AMPK staining in this subcellular compartment. Both AMPK and phospho-Thr172-AMPK human spermatozoa contents exhibit important individual variations. Moreover, active AMPK is predominant in the high motility sperm population, where shows a stronger intensity compared with the low motility sperm population. Inhibition of AMPK activity in human spermatozoa by CC treatment leads to a significant reduction in any sperm motility parameter analyzed: percent of motile sperm, sperm velocities, progressivity, and other motility coefficients. This work identifies and points out AMPK as a new molecular mechanism involved in human spermatozoa motility. Further AMPK implications in the clinical efficiency of assisted reproduction and in other reproductive areas need to be studied.

  1. Linguistic Diversity and Social Inclusion

    ERIC Educational Resources Information Center

    Piller, Ingrid; Takahashi, Kimie

    2011-01-01

    This introduction provides the framework for the special issue by describing the social inclusion agenda of neoliberal market democracies. While the social inclusion agenda has been widely adopted, social inclusion policies are often blind to the ways in which language proficiency and language ideologies mediate social inclusion in linguistically…

  2. Emergence and development of gut motility in the chicken embryo

    PubMed Central

    Chevalier, N. R.; Fleury, V.; Dufour, S.

    2017-01-01

    The gastrointestinal tract transports the food bolus by peristalsis. Gut motility starts at an early age in the developing embryo, well before it is required for nutrition of the organism. We present a comprehensive kinematic study of the emergence and physiological development of gut motility in all regions of the lower digestive tract of the chicken embryo from embryonic days E5 through E9. We characterized motility emergence time, propagation patterns, speed, frequency and amplitude of peristalsis waves. We found that the emergence of an uninterrupted circular ring of smooth muscle correlated with the appearance of propagative contractile waves, at E6 in the hindgut and midgut, and at E9 in the caecal appendix. We show that peristalsis at these stages is critically dependent on calcium and is not mediated by neurons as gut motility is insensitive to tetrodotoxin and takes place in the hindgut in the absence of neurons. We further demonstrate that motility also matures in ex-vivo organ culture. We compare our results to existing literature on zebrafish, mouse and human motility development, and discuss their chronological relationship with other major developmental events occurring in the chicken embryonic gut at these stages. Our work sets a baseline for further investigations of motility development in this important animal model. PMID:28222167

  3. Quorum sensing positively regulates flagellar motility in pathogenic Vibrio harveyi.

    PubMed

    Yang, Qian; Defoirdt, Tom

    2015-04-01

    Vibrios belonging to the Harveyi clade are among the major pathogens of aquatic organisms. Quorum sensing (QS) is essential for virulence of V. harveyi towards different hosts. However, most virulence factors reported to be controlled by QS to date are negatively regulated by QS, therefore suggesting that their impact on virulence is limited. In this study, we report that QS positively regulates flagellar motility. We found that autoinducer synthase mutants showed significantly lower swimming motility than the wild type, and the swimming motility could be restored by adding synthetic signal molecules. Further, motility of a luxO mutant with inactive QS (LuxO D47E) was significantly lower than that of the wild type and of a luxO mutant with constitutively maximal QS activity (LuxO D47A). Furthermore, we found that the expression of flagellar genes (both early, middle and late genes) was significantly lower in the luxO mutant with inactive QS when compared with wild type and the luxO mutant with maximal QS activity. Motility assays and gene expression also revealed the involvement of the quorum-sensing master regulator LuxR in the QS regulation of motility. Finally, the motility inhibitor phenamil significantly decreased the virulence of V. harveyi towards gnotobiotic brine shrimp larvae.

  4. Ion channels and calcium signaling in motile cilia

    PubMed Central

    Doerner, Julia F; Delling, Markus; Clapham, David E

    2015-01-01

    The beating of motile cilia generates fluid flow over epithelia in brain ventricles, airways, and Fallopian tubes. Here, we patch clamp single motile cilia of mammalian ependymal cells and examine their potential function as a calcium signaling compartment. Resting motile cilia calcium concentration ([Ca2+] ~170 nM) is only slightly elevated over cytoplasmic [Ca2+] (~100 nM) at steady state. Ca2+ changes that arise in the cytoplasm rapidly equilibrate in motile cilia. We measured CaV1 voltage-gated calcium channels in ependymal cells, but these channels are not specifically enriched in motile cilia. Membrane depolarization increases ciliary [Ca2+], but only marginally alters cilia beating and cilia-driven fluid velocity within short (~1 min) time frames. We conclude that beating of ependymal motile cilia is not tightly regulated by voltage-gated calcium channels, unlike that of well-studied motile cilia and flagella in protists, such as Paramecia and Chlamydomonas. DOI: http://dx.doi.org/10.7554/eLife.11066.001 PMID:26650848

  5. Emergence and development of gut motility in the chicken embryo.

    PubMed

    Chevalier, N R; Fleury, V; Dufour, S; Proux-Gillardeaux, V; Asnacios, A

    2017-01-01

    The gastrointestinal tract transports the food bolus by peristalsis. Gut motility starts at an early age in the developing embryo, well before it is required for nutrition of the organism. We present a comprehensive kinematic study of the emergence and physiological development of gut motility in all regions of the lower digestive tract of the chicken embryo from embryonic days E5 through E9. We characterized motility emergence time, propagation patterns, speed, frequency and amplitude of peristalsis waves. We found that the emergence of an uninterrupted circular ring of smooth muscle correlated with the appearance of propagative contractile waves, at E6 in the hindgut and midgut, and at E9 in the caecal appendix. We show that peristalsis at these stages is critically dependent on calcium and is not mediated by neurons as gut motility is insensitive to tetrodotoxin and takes place in the hindgut in the absence of neurons. We further demonstrate that motility also matures in ex-vivo organ culture. We compare our results to existing literature on zebrafish, mouse and human motility development, and discuss their chronological relationship with other major developmental events occurring in the chicken embryonic gut at these stages. Our work sets a baseline for further investigations of motility development in this important animal model.

  6. Inclusion Body Myositis

    PubMed Central

    Dimachkie, Mazen M.; Barohn, Richard J.

    2012-01-01

    The idiopathic inflammatory myopathies are a group of rare disorders that share many similarities. These include dermatomyositis (DM), polymyositis (PM), necrotizing myopathy (NM), and sporadic inclusion body myositis (IBM). Inclusion body myositis is the most common idiopathic inflammatory myopathy after age 50 and it presents with chronic proximal leg and distal arm asymmetric mucle weakness. Despite similarities with PM, it is likely that IBM is primarily a degenerative disorder rather than an inflammatory muscle disease. Inclusion body myositis is associated with a modest degree of creatine kinase (CK) elevation and an abnormal electromyogram demonstrating an irritative myopathy with some chronicity. The muscle histopathology demonstrates inflammatory exudates surrounding and invading nonnecrotic muscle fibers often times accompanied by rimmed vacuoles. In this chapter, we review sporadic IBM. We also examine past, essentially negative, clinical trials in IBM and review ongoing clinical trials. For further details on DM, PM, and NM, the reader is referred to the idiopathic inflammatory myopathies chapter. PMID:23117948

  7. Comparative transcriptomics with a motility-deficient mutant leads to identification of a novel polysaccharide secretion system in Nostoc punctiforme.

    PubMed

    Risser, Douglas D; Meeks, John C

    2013-02-01

    Many filamentous cyanobacteria are capable of gliding motility by an undefined mechanism. Within the heterocyst-forming clades, some strains, such as the Nostoc spp. and Fisherella spp., are motile only as specialized filaments termed hormogonia. Here we report on the phenotype of inactivation of a methyl-accepting chemotaxis-like protein in Nostoc punctiforme, designated HmpD. The gene hmpD was found to be essential for hormogonium development, motility and polysaccharide secretion. Comparative global transcriptional profiling of the ΔhmpD strain demonstrated that HmpD has a profound effect on the transcriptional programme of hormogonium development, influencing approximately half of the genes differentially transcribed during differentiation. Utilizing this transcriptomic data, we identified a gene locus, designated here as hps, that appears to encode for a novel polysaccharide secretion system. Transcripts for the genes in the hps locus are upregulated in two steps, with the second step dependent on HmpD. Deletion of hpsA, hpsBCD or hpsEFG resulted in the complete loss of motility and polysaccharide secretion, similar to deletion of hmpD. Genes in the hps locus are highly conserved in the filamentous cyanobacteria, but generally absent in unicellular strains, implying a common mechanism of motility unique to the filamentous cyanobacteria.

  8. Detection of rare antigen-presenting cells through T cell-intrinsic meandering motility, mediated by Myo1g.

    PubMed

    Gérard, Audrey; Patino-Lopez, Genaro; Beemiller, Peter; Nambiar, Rajalakshmi; Ben-Aissa, Khadija; Liu, Yin; Totah, Fadi J; Tyska, Matthew J; Shaw, Stephen; Krummel, Matthew F

    2014-07-31

    To mount an immune response, T lymphocytes must successfully search for foreign material bound to the surface of antigen-presenting cells. How T cells optimize their chances of encountering and responding to these antigens is unknown. T cell motility in tissues resembles a random or Levy walk and is regulated in part by external factors including chemokines and lymph-node topology, but motility parameters such as speed and propensity to turn may also be cell intrinsic. Here we found that the unconventional myosin 1g (Myo1g) motor generates membrane tension, enforces cell-intrinsic meandering search, and enhances T-DC interactions during lymph-node surveillance. Increased turning and meandering motility, as opposed to ballistic motility, is enhanced by Myo1g. Myo1g acts as a "turning motor" and generates a form of cellular "flânerie." Modeling and antigen challenges show that these intrinsically programmed elements of motility search are critical for the detection of rare cognate antigen-presenting cells.

  9. Swimming with protists: perception, motility and flagellum assembly.

    PubMed

    Ginger, Michael L; Portman, Neil; McKean, Paul G

    2008-11-01

    In unicellular and multicellular eukaryotes, fast cell motility and rapid movement of material over cell surfaces are often mediated by ciliary or flagellar beating. The conserved defining structure in most motile cilia and flagella is the '9+2' microtubule axoneme. Our general understanding of flagellum assembly and the regulation of flagellar motility has been led by results from seminal studies of flagellate protozoa and algae. Here we review recent work relating to various aspects of protist physiology and cell biology. In particular, we discuss energy metabolism in eukaryotic flagella, modifications to the canonical assembly pathway and flagellum function in parasite virulence.

  10. Motility, Force Generation, and Energy Consumption of Unicellular Parasites.

    PubMed

    Hochstetter, Axel; Pfohl, Thomas

    2016-07-01

    Motility is a key factor for pathogenicity of unicellular parasites, enabling them to infiltrate and evade host cells, and perform several of their life-cycle events. State-of-the-art methods of motility analysis rely on a combination of optical tweezers with high-resolution microscopy and microfluidics. With this technology, propulsion forces, energies, and power generation can be determined so as to shed light on the motion mechanisms, chemotactic behavior, and specific survival strategies of unicellular parasites. With these new tools in hand, we can elucidate the mechanisms of motility and force generation of unicellular parasites, and identify ways to manipulate and eventually inhibit them.

  11. Effects of trifluoromethyl ketones on the motility of Proteus vulgaris.

    PubMed

    Wolfart, Krisztina; Molnar, Annamaria; Kawase, Masami; Motohashi, Noboru; Molnar, Joseph

    2004-09-01

    In the present study, we showed the inhibition of motility by trifluoromethyl ketone (TF) derivatives (1-8) in Proteus vulgaris (P. vulgaris) cultures. Among them, 1-(2-benzoxazoyl)-3,3,3-trifluoro-2-propanone (1) showed a much stronger inhibitory effect on the motility of P. vulgaris than other TF compounds at 10% MIC. Our results suggest the possibility of an inhibitory action of TF compounds on the proton motive forces by affecting the action of biological motor and proton efflux in the membranes, resulting in a reduction of the ratio of running and the increased number of tumbling and non-motile cells.

  12. The Chicago classification of motility disorders: an update.

    PubMed

    Roman, Sabine; Gyawali, C Prakash; Xiao, Yinglian; Pandolfino, John E; Kahrilas, Peter J

    2014-10-01

    The Chicago Classification defines esophageal motility disorders in high resolution manometry. This is based on individual scoring of 10 swallows performed in supine position. Disorders of esophago-gastric junction (EGJ) outflow obstruction are defined by a median integrated relaxation pressure above the limit of normal and divided into 3 achalasia subtypes and EGJ outflow obstruction. Major motility disorders (aperistalsis, distal esophageal spasm, and hypercontractile esophagus) are patterns not encountered in controls in the context of normal EGJ relaxation. Finally with the latest version of the Chicago Classification, only two minor motor disorders are considered: ineffective esophageal motility and fragmented peristalsis.

  13. Single-filament kinetic studies provide novel insights into regulation of actin-based motility

    PubMed Central

    Shekhar, Shashank; Carlier, Marie-France

    2016-01-01

    Polarized assembly of actin filaments forms the basis of actin-based motility and is regulated both spatially and temporally. Cells use a variety of mechanisms by which intrinsically slower processes are accelerated, and faster ones decelerated, to match rates observed in vivo. Here we discuss how kinetic studies of individual reactions and cycles that drive actin remodeling have provided a mechanistic and quantitative understanding of such processes. We specifically consider key barbed-end regulators such as capping protein and formins as illustrative examples. We compare and contrast different kinetic approaches, such as the traditional pyrene-polymerization bulk assays, as well as more recently developed single-filament and single-molecule imaging approaches. Recent development of novel biophysical methods for sensing and applying forces will in future allow us to address the very important relationship between mechanical stimulus and kinetics of actin-based motility. PMID:26715420

  14. Colloidal motility and patterning by physical chemotaxis

    NASA Astrophysics Data System (ADS)

    Palacci, Jeremie; Abecassis, Benjamin; Cottin-Bizonne, Cecile; Ybert, Christophe; Bocquet, Lyderic

    2009-11-01

    We developped a microfluidic setup to show the motility of colloids or biomolecules under a controlled salt gradient thanks to the diffusiophoresis phenomenon [1,2]. We can therefore mimic chemotaxis on simple physical basis with thrilling analogies with the biological chemotaxis of E. Coli bacteria: salt dependance of the velocity [3] and log-sensing behavior [4]. In addition with a temporally tunable gradient we show we can generate an effective osmotic potential to trap colloids or DNA. These experimental observations are supported by numerical simulations and an asymptotic ratchet model. Finally, we use these traps to generate various patterns and because concentration gradients are ubiquitous in nature, we question for the role of such a mecanism in morphogenesis [5] or positioning perspectives in cells [6]. [4pt] [1] B. Abecassis, C. Cottin-Bizonne, C. Ybert, A. Ajdari, and L. Bocquet, Nat. Mat., 7(10):785--789, 2008. [2] Anderson, Ann. Rev. Fluid Mech, 21, 1989. [3] Y. L. Qi and J. Adler, PNAS, 86(21):8358--8362, 1989. [4] Y. V. Kalinin, L. L. Jiang, Y. H. Tu, and M. M. Wu, Biophys. J., 96(6):2439--2448, 2009. [4] J. B. Moseley, A. Mayeux, A. Paoletti, and P. Nurse, Nat., 459(7248):857--U8, 2009. [6] L. Wolpert, Dev., 107:3--12, 1989

  15. Activated Membrane Patches Guide Chemotactic Cell Motility

    PubMed Central

    Hecht, Inbal; Skoge, Monica L.; Charest, Pascale G.; Ben-Jacob, Eshel; Firtel, Richard A.; Loomis, William F.; Levine, Herbert; Rappel, Wouter-Jan

    2011-01-01

    Many eukaryotic cells are able to crawl on surfaces and guide their motility based on environmental cues. These cues are interpreted by signaling systems which couple to cell mechanics; indeed membrane protrusions in crawling cells are often accompanied by activated membrane patches, which are localized areas of increased concentration of one or more signaling components. To determine how these patches are related to cell motion, we examine the spatial localization of RasGTP in chemotaxing Dictyostelium discoideum cells under conditions where the vertical extent of the cell was restricted. Quantitative analyses of the data reveal a high degree of spatial correlation between patches of activated Ras and membrane protrusions. Based on these findings, we formulate a model for amoeboid cell motion that consists of two coupled modules. The first module utilizes a recently developed two-component reaction diffusion model that generates transient and localized areas of elevated concentration of one of the components along the membrane. The activated patches determine the location of membrane protrusions (and overall cell motion) that are computed in the second module, which also takes into account the cortical tension and the availability of protrusion resources. We show that our model is able to produce realistic amoeboid-like motion and that our numerical results are consistent with experimentally observed pseudopod dynamics. Specifically, we show that the commonly observed splitting of pseudopods can result directly from the dynamics of the signaling patches. PMID:21738453

  16. Structures of the Toxoplasma gliding motility adhesin

    PubMed Central

    Song, Gaojie; Springer, Timothy A.

    2014-01-01

    Micronemal protein 2 (MIC2) is the key adhesin that supports gliding motility and host cell invasion by Toxoplasma gondii. With a von Willebrand factor A (VWA) domain and six thrombospondin repeat domains (TSR1–6) in its ectodomain, MIC2 connects to the parasite actomyosin system through its cytoplasmic tail. MIC2-associated protein (M2AP) binds noncovalently to the MIC2 ectodomain. MIC2 and M2AP are stored in micronemes as proforms. We find that the MIC2–M2AP ectodomain complex is a highly elongated 1:1 monomer with M2AP bound to the TSR6 domain. Crystal structures of N-terminal fragments containing the VWA and TSR1 domains for proMIC2 and MIC2 reveal a closed conformation of the VWA domain and how it associates with the TSR1 domain. A long, proline-rich, disulfide-bonded pigtail loop in TSR1 overlaps the VWA domain. Mannose α-C-linked to Trp-276 in TSR1 has an unusual 1C4 chair conformation. The MIC2 VWA domain includes a mobile α5-helix and a 22-residue disordered region containing two disulfide bonds in place of an α6-helix. A hydrophobic residue in the prodomain binds to a pocket adjacent to the α7-helix that pistons in opening of the VWA domain to a putative high-affinity state. PMID:24639528

  17. Polymer confinement and bacterial gliding motility

    NASA Astrophysics Data System (ADS)

    Jeon, Junhwan; Dobrynin, Andrey

    2006-03-01

    Cyanobacteria and myxobacteria use slime secretion for gliding motility over surfaces. In cyanobacteria the slime is extruded from the nozzle-like pores of 14-16 nm outer diameter and approximately 7nm inner diameter located near the septa that separate the cells of a filament. The pores are inclined at an angle of 30-40 degrees relative to the cell axes, and are oppositely directed on both sides of the septum. Such pore orientation provides directionality for the slime secretion as well as cell motion. To understand the mechanism of gliding motion and its relation to slime polymerization, we have performed molecular dynamics simulations of a molecular nozzle with growing inside polymer chains. These simulations show that the compression of polymer chains inside the nozzle is a driving force for its propulsion. There is a linear relationship between the average nozzle velocity and the chain polymerization rate with a proportionality coefficient dependent on the geometric characteristics of the nozzle such as its length and friction coefficient. This minimal model of the molecular engine was used to explain the gliding motion of cyanobacteria and myxobacteria over surfaces.

  18. Shear alters motility of Escherichia coli

    NASA Astrophysics Data System (ADS)

    Molaei, Mehdi; Jalali, Maryam; Sheng, Jian

    2013-11-01

    Understanding of locomotion of microorganisms in shear flows drew a wide range of interests in microbial related topics such as biological process including pathogenic infection and biophysical interactions like biofilm formation on engineering surfaces. We employed microfluidics and digital holography microscopy to study motility of E. coli in shear flows. We controlled the shear flow in three different shear rates: 0.28 s-1, 2.8 s-1, and 28 s-1 in a straight channel with the depth of 200 μm. Magnified holograms, recorded at 15 fps with a CCD camera over more than 20 minutes, are analyzed to obtain 3D swimming trajectories and subsequently used to extract shear responses of E.coli. Thousands of 3-D bacterial trajectories are tracked. The change of bacteria swimming characteristics including swimming velocity, reorientation, and dispersion coefficient are computed directly for individual trajectory and ensemble averaged over thousands of realizations. The results show that shear suppresses the bacterial dispersions in bulk but promote dispersions near the surface contrary to those in quiescent flow condition. Ongoing analyses are focusing to quantify effect of shear rates on tumbling frequency and reorientation of cell body, and its implication in locating the hydrodynamic mechanisms for shear enhanced angular scattering. NIH, NSF, GoMRI.

  19. Eye Motility Alterations in Retinitis Pigmentosa.

    PubMed

    Migliorini, Raffaele; Comberiati, Anna Maria; Galeoto, Giovanni; Fratipietro, Manuela; Arrico, Loredana

    2015-01-01

    Purpose. We evaluated a sample of individuals with retinitis pigmentosa (RP) with the aim of assessing the presence or absence of ocular motility (OM) disorders. Materials and Methods. We included 23 out of the 25 individuals from the sample (9 females and 14 males) with an average visual acuity of 6/10. Results. The cover test about the vertical deviation in near distance showed an r/l in 3.45% and an l/r in 6.9%. The assessment of OM showed that 39.1% of the sample had a severe hyperfunction of the IO of the right eye and a severe hyperfunction (34.5%) of the SO of the left eye; 21.8% had a moderate hypofunction of right SO with a moderate percentage of hypofunction of 17.5% for the SO of the left eye; 30.5%, however, showed a serious hypofunction of the SR of both eyes; 21.7% of the sample showed a hyperfunction in both eyes of the IR. Conclusion. This alteration, however, is not attributable to either a high refractive defect (medium-low myopia: -1 diopter ±3 SD) or to a severely impaired binocular vision (visual acuity, motor fusion, and stereopsis are normal or within a range of values commonly accepted). Therefore, the disorders of OM lead to a genetic origin.

  20. Tachykinins and in vivo gut motility.

    PubMed

    Sarna, S K

    1999-08-01

    The gut smooth muscle in the intact conscious state exhibits three distinct types of contractions: rhythmic phasic contractions, tone, and ultrapropulsive contractions. The motility functions of these contractions differ markedly. The phasic contractions mix and propel the ingested food in an orderly fashion so that the nutrients can be absorbed. The ultrapropulsive contractions are of two types, giant migrating contractions (GMCs) and retrograde giant contractions (RGCs). GMCs produce mass movements in the caudal direction and RGCs in the oral direction. GMCs are associated with the symptoms of diarrhea, abdominal cramping, tenesmus, and urgency of defecation. The RGCs regurgitate the contents of the upper small intestine into the stomach in preparation of their expulsion by the somatomotor response. Tachykinins and their receptors are strategically located on the enteric neurons and smooth muscle cells to regulate the above contractions. Recent findings show that NK-1 receptors located on colonic circular smooth muscle cells may mediate colonic GMCs, whereas NK-3 receptors located on presynaptic neurons may mediate the small intestinal GMCs. The molecular and cellular mechanisms of stimulation of RGCs are not known. NK-1 receptor antagonists have shown potential therapeutic effects on vomiting induced by a variety of stimuli in experimental animals.

  1. A 20-year perspective--from Journal of Gastrointestinal Motility to Neurogastroenterology and Motility.

    PubMed

    Wingate, D L

    2008-05-01

    This review traces the origins of this journal as the consequence of a revolution in academic publishing that started in Oxford 50 years ago. It also traces the expansion of the field of gastrointestinal motility by the development of new methodology that prompted both the creation of learned societies and a role for a journal devoted to this field. The problems that arose because the new journal was an 'orphan journal' lacking a parent society are recounted, as are the events that eventually led to its adoption. Finally, the introduction of the term 'neurogastroenterology' into scientific and clinical parlance is explained.

  2. Nanotubular Toughening Inclusions

    NASA Technical Reports Server (NTRS)

    Park, Cheol (Inventor); Working, Dennis C. (Inventor); Siochi, Emilie J. (Inventor); Harrison, Joycelyn S. (Inventor)

    2015-01-01

    Conventional toughening agents are typically rubbery materials or small molecular weight molecules, which mostly sacrifice the intrinsic properties of a matrix such as modulus, strength, and thermal stability as side effects. On the other hand, high modulus inclusions tend to reinforce elastic modulus very efficiently, but not the strength very well. For example, mechanical reinforcement with inorganic inclusions often degrades the composite toughness, encountering a frequent catastrophic brittle failure triggered by minute chips and cracks. Thus, toughening generally conflicts with mechanical reinforcement. Carbon nanotubes have been used as efficient reinforcing agents in various applications due to their combination of extraordinary mechanical, electrical, and thermal properties. Moreover, nanotubes can elongate more than 20% without yielding or breaking, and absorb significant amounts of energy during deformation, which enables them to also be an efficient toughening agent, as well as excellent reinforcing inclusion. Accordingly, an improved toughening method is provided by incorporating nanotubular inclusions into a host matrix, such as thermoset and thermoplastic polymers or ceramics without detrimental effects on the matrix's intrinsic physical properties.

  3. Nanotubular Toughening Inclusions

    NASA Technical Reports Server (NTRS)

    Park, Cheol (Inventor); Working, Dennis C. (Inventor); Siochi, Emilie J. (Inventor); Harrison, Joycelyn S. (Inventor)

    2017-01-01

    Conventional toughening agents are typically rubbery materials or small molecular weight molecules, which mostly sacrifice the intrinsic properties of a matrix such as modulus, strength, and thermal stability as side effects. On the other hand, high modulus inclusions tend to reinforce elastic modulus very efficiently, but not the strength very well. For example, mechanical reinforcement with inorganic inclusions often degrades the composite toughness, encountering a frequent catastrophic brittle failure triggered by minute chips and cracks. Thus, toughening generally conflicts with mechanical reinforcement. Carbon nanotubes have been used as efficient reinforcing agents in various applications due to their combination of extraordinary mechanical, electrical, and thermal properties. Moreover, nanotubes can elongate more than 20% without yielding or breaking, and absorb significant amounts of energy during deformation, which enables them to also be an efficient toughening agent, as well as excellent reinforcing inclusion. Accordingly, an improved toughening method is provided by incorporating nanotubular inclusions into a host matrix, such as thermoset and thermoplastic polymers or ceramics without detrimental effects on the intrinsic physical properties of the matrix.

  4. Bacterial inclusion body purification.

    PubMed

    Seras-Franzoso, Joaquin; Peternel, Spela; Cano-Garrido, Olivia; Villaverde, Antonio; García-Fruitós, Elena

    2015-01-01

    Purification of bacterial inclusion bodies (IBs) is gaining importance due to the raising of novel applications for this type of submicron particulate protein clusters, with potential uses in the biomedical field among others. Here, we present two optimized methods to purify IBs adapting classical procedures to the material nature as well as the requirements of its final application.

  5. Against Being Inclusive

    ERIC Educational Resources Information Center

    Carlson, Jeffrey

    2016-01-01

    The term "inclusive excellence," made popular by the Association of American Colleges and Universities and adopted by many schools across the country is in some ways unfortunate, in that the concept of "including," arguably, assumes the priority and ongoing dominance of a given reality into which one may (or may not) be granted…

  6. Positive Inclusion Experiences.

    ERIC Educational Resources Information Center

    Ensign, Arselia, Ed.

    1996-01-01

    This guide focuses on the use of low-end technology to make education more inclusive for children and adolescents with disabilities. The definition of "assistive technology" is discussed, and low-end technology is defined as simple modification/adaptation of toys and games, design and construction of simple switching devices, and the…

  7. Collaborative Support for Inclusion

    ERIC Educational Resources Information Center

    Sanahuja-Gavaldà, Josep M.; Olmos-Rueda, Patricia; Morón-Velasco, Mar

    2016-01-01

    Nowadays, in Catalonia, students with autism spectrum disorders (ASD) are increasingly in regular schools although their presence, participation, learning and success are unequal. Barriers towards inclusion often depend on how to organise supporting at regular schools and the teachers' collaboration during this process. In this paper, the support…

  8. Relationships in Inclusive Classrooms

    ERIC Educational Resources Information Center

    Santos, Graça Duarte; Sardinha, Susana; Reis, Silvia

    2016-01-01

    Climate in the classroom is one of the determining factors in the development of practices in Inclusive Education. Many factors contribute to the climate in the classroom. However, there are predominance on affective-relational factors, with impact on action, norms and values, social interactions and learning processes. In this paper, the authors…

  9. Education for Inclusion

    ERIC Educational Resources Information Center

    Preece, Julia

    2006-01-01

    Poverty can be both a consequence of, and contributory factor to, educational exclusion. This paper argues that poverty and exclusion are multidimensional. They require a multisectoral and multilevel approach in education if the most vulnerable sectors of society are to benefit from initiatives to turn exclusion into inclusion. This paper also…

  10. Inclusion on the Bookshelf

    ERIC Educational Resources Information Center

    Jackson, Camille

    2009-01-01

    Three decades have passed since federal law mandated inclusion--ending, officially at least, a system that segregated students with disabilities from the rest of the student population. The publishing world has yet to catch up. In children's books, characters with disabilities often inhabit their own separate world, where disability is the only…

  11. Exploring Inclusive Pedagogy

    ERIC Educational Resources Information Center

    Florian, Lani; Black-Hawkins, Kristine

    2011-01-01

    This paper reports on a study designed to examine teachers' craft knowledge of their practice of "inclusion" in terms of what they do, why and how. The research approach offers an important alternative to studies of students with "additional needs" and the search to articulate the specialist knowledge and skill required to…

  12. Inclusion Strategies that Work

    ERIC Educational Resources Information Center

    Hammel, Alice M.

    2004-01-01

    Many school systems are moving toward an inclusion model for teaching special learners in which all students are included in general classrooms. The basic premise is that all students should first be placed in the general classroom. Students receive as many necessary supplementary aids and services as possible in the general classroom, and then,…

  13. On the Dirt Road to Inclusion

    ERIC Educational Resources Information Center

    Wiazowski, Jaroslaw

    2012-01-01

    Inclusive education in the Republic of South Africa has been codified and written down in the form of White Papers. From the legislative point of view, the situation is clear. The reality however shows that the implementation of the law is still at its infancy. Students with visual impairments are practically confined to being educated in…

  14. Inclusion and Equity in Australian Secondary Schools

    ERIC Educational Resources Information Center

    Paterson, David; Graham, Lorraine; Stevens, Robert

    2014-01-01

    This paper presents findings from a large-scale, in-depth study of secondary schools in one Australian state that were achieving exceptional outcomes. The element of that study on which this paper focuses is equity and inclusion. We examine the Equity programs operating in seven sites where schools were including students experiencing some form of…

  15. Strongyloides stercoralis hyperinfection associated with impaired intestinal motility disorder

    PubMed Central

    Figueira, Cláudia Frangioia; Cos, Lynda Dorene; Ussami, Edson Yassushi; Otoch, José Pinhata; Felipe-Silva, Aloisio

    2015-01-01

    Infection by Strongyloides stercoralis is a highly prevalent helminthiasis, which is mostly distributed in the tropical and subtropical regions of the world. Although a substantial number of cases are asymptomatic or paucisymtomatic, severe and life-threatening forms of this infection still occur and not infrequently is lately diagnosed. Gram-negative bacteria septicemia, which frequently accompanies the severe helminthiasis, contributes to the high mortality rate. Severe infection is invariably triggered by any imbalance in the host's immunity, favoring the auto-infective cycle, which increases the intraluminal parasite burden enormously. Clinical presentation of severe cases is varied, and diagnosis requires a high suspicion index. Acute abdomen has been reported in association with S. stercoralis infection, but intestinal necrosis is rarely found during the surgical approach. The authors report the case of a man who sought the emergency unit with recent onset abdominal pain. Clinical and imaging features were consistent with obstructive acute abdomen. Scattered adhesions and a necrotic ileal segment with a tiny perforation represented the surgical findings. The patient outcome was unfavorable and respiratory distress required an open lung biopsy. Both surgical specimens showed S. stercoralis infection. Unfortunately the patient underwent multiple organ failure and septicemia, and subsequently died. The authors call attention to the finding of intestinal necrosis and impaired intestinal motility disorder as possibilities for the diagnosis and risk factor, respectively, for a severe infection of S. stercoralis. PMID:26484331

  16. Exopolysaccharide microchannels direct bacterial motility and organize multicellular behavior

    PubMed Central

    Berleman, James E; Zemla, Marcin; Remis, Jonathan P; Liu, Hong; Davis, Annie E; Worth, Alexandra N; West, Zachary; Zhang, Angela; Park, Hanwool; Bosneaga, Elena; van Leer, Brandon; Tsai, Wenting; Zusman, David R; Auer, Manfred

    2016-01-01

    The myxobacteria are a family of soil bacteria that form biofilms of complex architecture, aligned multilayered swarms or fruiting body structures that are simple or branched aggregates containing myxospores. Here, we examined the structural role of matrix exopolysaccharide (EPS) in the organization of these surface-dwelling bacterial cells. Using time-lapse light and fluorescence microscopy, as well as transmission electron microscopy and focused ion beam/scanning electron microscopy (FIB/SEM) electron microscopy, we found that Myxococcus xanthus cell organization in biofilms is dependent on the formation of EPS microchannels. Cells are highly organized within the three-dimensional structure of EPS microchannels that are required for cell alignment and advancement on surfaces. Mutants lacking EPS showed a lack of cell orientation and poor colony migration. Purified, cell-free EPS retains a channel-like structure, and can complement EPS− mutant motility defects. In addition, EPS provides the cooperative structure for fruiting body formation in both the simple mounds of M. xanthus and the complex, tree-like structures of Chondromyces crocatus. We furthermore investigated the possibility that EPS impacts community structure as a shared resource facilitating cooperative migration among closely related isolates of M. xanthus. PMID:27152937

  17. Exopolysaccharide microchannels direct bacterial motility and organize multicellular behavior.

    PubMed

    Berleman, James E; Zemla, Marcin; Remis, Jonathan P; Liu, Hong; Davis, Annie E; Worth, Alexandra N; West, Zachary; Zhang, Angela; Park, Hanwool; Bosneaga, Elena; van Leer, Brandon; Tsai, Wenting; Zusman, David R; Auer, Manfred

    2016-11-01

    The myxobacteria are a family of soil bacteria that form biofilms of complex architecture, aligned multilayered swarms or fruiting body structures that are simple or branched aggregates containing myxospores. Here, we examined the structural role of matrix exopolysaccharide (EPS) in the organization of these surface-dwelling bacterial cells. Using time-lapse light and fluorescence microscopy, as well as transmission electron microscopy and focused ion beam/scanning electron microscopy (FIB/SEM) electron microscopy, we found that Myxococcus xanthus cell organization in biofilms is dependent on the formation of EPS microchannels. Cells are highly organized within the three-dimensional structure of EPS microchannels that are required for cell alignment and advancement on surfaces. Mutants lacking EPS showed a lack of cell orientation and poor colony migration. Purified, cell-free EPS retains a channel-like structure, and can complement EPS(-) mutant motility defects. In addition, EPS provides the cooperative structure for fruiting body formation in both the simple mounds of M. xanthus and the complex, tree-like structures of Chondromyces crocatus. We furthermore investigated the possibility that EPS impacts community structure as a shared resource facilitating cooperative migration among closely related isolates of M. xanthus.

  18. Motility and peristaltic flow in maintaining microbiome populations

    NASA Astrophysics Data System (ADS)

    Mirbagheri, Seyed Amir; Fu, Henry C.

    2016-11-01

    Bacteria are an important component of the microbiome in the digestive tract, and must be able to maintain their population despite the fact that the contents of the intestines are constantly flowing towards evacuation. Many bacteria accomplish this by colonizing the surfaces of the intestines where flows diminish, but some species live in the lumen. We attempt to address whether swimming motility of these species plays an important role in maintaining bacterial population in the face of peristaltic pumping out of the intestine. Using a two-dimensional model of peristaltic flows induced by small-amplitude traveling waves we examine the Lagrangian trajectories of passive bacteria as well as motile bacteria, which are treated as Brownian particles undergoing enhanced diffusion due to the bacteria's run-and-tumble motility. We examine how the densities of growing populations of bacteria depend on the combination of motility and peristaltic flow.

  19. Molecular mechanism of fluoroquinolones modulation on corneal fibroblast motility.

    PubMed

    Chen, Tsan-Chi; Tsai, Tzu-Yun; Chang, Shu-Wen

    2016-04-01

    Topical fluoroquinolones are widely used to prevent ocular infections after ophthalmic surgery. However, they have been shown to affect the corneal cell motility, whose mechanism remains indefinite. The purpose of this study was to investigate how fluoroquinolones affect corneal stromal cell motility. Human corneal fibroblasts (HCFs) were incubated in ciprofloxacin (CIP), levofloxacin (LEV), or moxifloxacin (MOX) at 0, 10, 50, and 100 μg/ml for up to 3 days. Effect of CIP, LEV, or MOX on HCF migration was monitored using migration assay. HCF viability was determined by WST-1 assay. Expression of focal adhesion kinase (FAK), paxillin (PXN), and their phosphorylated forms were analyzed by immunoblotting. Binding affinity between FAK and PXN was determined by co-immunoprecipitation. Our results revealed that CIP and MOX, but not LEV, noticeably retarded HCF migration. HCF proliferation was significantly reduced by CIP (38.2%), LEV (29.5%), and MOX (21.3%), respectively (p = 0.002). CIP and MOX suppressed the phosphorylation of PXN at tyrosines (10.2 ± 4.3%, p < 0.001; 11.7 ± 2.4%, p < 0.001, respectively), including tyrosine 118 (33.3 ± 5.2%, p < 0.001; 34.0 ± 4.4%, p < 0.001, respectively). CIP and MOX diminished the binding affinity between FAK and PXN (8.2 ± 1.8%, p < 0.001; 9.0 ± 4.5%, p < 0.001, respectively). Nevertheless, tyrosine dephosphorylation and FAK dissociation of PXN were not found in LEV-treated HCFs. None of these fluoroquinolones affect phosphorylation of FAK-Y397. We conclude that CIP and MOX, but not LEV, might delay corneal fibroblast migration via interfering with recruitment of PXN to focal adhesions and dephosphorylation of PXN at the tyrosines.

  20. Inclusion body myositis with granuloma formation in muscle tissue.

    PubMed

    Sakai, Kenji; Ikeda, Yoshihisa; Ishida, Chiho; Matsumoto, Yasuko; Ono, Kenjiro; Iwasa, Kazuo; Yamada, Masahito

    2015-09-01

    Inclusion body myositis is a form of inflammatory myopathy. We identified 4 cases of inclusion body myositis showing granuloma formation in muscle tissue and aimed to assess the features of this atypical form of inclusion body myositis. We retrospectively reviewed consecutive patients who satisfied European Neuromuscular Centre IBM Research Diagnostic Criteria 2011. Then, we assessed clinical profiles and pathological findings in patients with inclusion body myositis with granuloma and compared these findings with those of typical inclusion body myositis without granuloma. We identified 15 patients with inclusion body myositis. Four patients showed granuloma formation in muscle tissue in addition to typical pathological features of inclusion body myositis. Granulomas comprised a mixture of inflammatory cells, such as macrophages, epithelioid histiocytic cells, and lymphocytes. One patient was found to have mediastinal granulomatous lymphadenopathy; however, the evidence in other patients was insufficient for a diagnosis of systemic sarcoidosis. There were no significant differences between groups with and without granuloma regarding clinical manifestations, laboratory findings, response to immunomodulating therapies, or myopathological profiles. We established a new form of inclusion body myositis showing granuloma formation in muscle tissue. Inclusion body myositis and granuloma formation could have identical pathomechanisms concerning dysregulation of autophagy.

  1. Motility and Adhesiveness in Human Neutrophils

    PubMed Central

    Smith, C. Wayne; Hollers, James C.; Patrick, Richard A.; Hassett, Clare

    1979-01-01

    Human peripheral blood neutrophils (PMN) obtained from healthy adults were examined in vitro with techniques adapted to assess the effects of chemotactic factors (CF) on cellular configuration and adhesiveness. The results were compared with those that use certain conventional techniques for assessing chemotaxis and chemokinesis. Exposure of PMN to N-formyl-l-methionyl-l-phenylalanine (f-Met-Phe), zymosan-activated serum, bacterial chemotactic factor, or a low molecular weight chemotactic factor from activated serum (C5a) in the absence of a gradient resulted in a change in cellular shape from a spherical to a polarized configuration in a high percentage of cells. This occurred rapidly in suspension, under conditions designed to exclude a role for cell adhesiveness, and was reversible upon removal of the CF. Restimulation of cells with the CF resulted in reappearance of the polarized configuration to the same extent as on initial stimulation with one exception: f-Met-Phe pretreated cells failed to respond to f-Met-Phe, though they responded fully to the other CF. Each CF caused a significant increase in PMN attachment to protein-coated glass. This enhanced adhesiveness was not reversible upon removal of the CF when the cells were treated under conditions shown to produce chemotactic deactivation. Cells treated under these conditions also exhibited significantly reduced motility on glass and in micropore filters in the absence of a gradient of CF. Bacterial chemotactic factor, even at high concentrations, failed to produce deactivation and did not cause a sustained enhancement of adhesiveness. Images PMID:372238

  2. Tubulin protofilaments and kinesin-dependent motility

    PubMed Central

    1992-01-01

    . This indicates that even if these microtubules differ in surface lattice, this does not affect the motility. PMID:1500429

  3. Evaluation of regional and whole gut motility using the wireless motility capsule: relevance in clinical practice

    PubMed Central

    Tran, Khoa; Brun, Rita

    2012-01-01

    The wireless motility capsule (WMC) is an ambulatory noninvasive and nonradioactive diagnostic sensor that continuously samples intraluminal pH, temperature, and pressure as it moves through the gastrointestinal (GI) tract. This review summarizes the data obtained in clinical trials with the WMC and discusses its role in clinical practice. The United States Food and Drug Administration has approved the SmartPill GI monitoring system for the evaluation of gastric emptying time in patients with suspected gastroparesis, the evaluation of colonic transit time in patients with suspected chronic constipation, and for the characterization of pressure profiles from the antrum and duodenum. Clinical studies have shown that WMC-measured GI transit times can distinguish patients with motility abnormalities similarly to conventional testing. However, the WMC offers the advantage of providing a full GI-tract profile, enabling the detection of multiregional GI transit abnormalities in patients with suspected upper or lower GI dysmotility. The WMC also characterizes pressure profiles of the GI tract and impaired pressure profile limits are reported for the antrum and duodenum. In comparison with manometry, interpretations of pressure measurements obtained by the WMC are limited by an inability to detect a peristaltic pressure wave front, and further investigation is required to develop clinical applications. Clinical studies with the WMC indicated that it should be considered for the evaluation of regional and whole gut transit time in patients with suspected upper or lower dysmotility, particularly if there are concerns about multiregional dysmotility. PMID:22778790

  4. Effect of surface chemistry on in vitro actomyosin motility

    NASA Astrophysics Data System (ADS)

    Hanson, Kristi L.; Solana, Gerardin; Nicolau, Dan V.

    2005-02-01

    A variety of surface coatings were evaluated for their ability to promote in vitro actomyosin motility. Rabbit skeletal muscle heavy meromyosin (HMM) was adsorbed to uncoated glass and to surfaces coated with nitrocellulose, poly(methyl methacrylate) (PMMA), poly(butyl methacrylate) (PBMA), poly(tert-butyl methacrylate (PtBMA), polystyrene (PS) and hexamethyldisilazane (HMDS), and the myosin driven movement of fluorescently labeled actin filaments was recorded using epifluorescence microscopy. HMDS and uncoated glass did not support actomyosin motility, while mean velocities on other surfaces ranged from 1.7 μm sec-1 (PtBMA) to 3.5 μm sec-1 (NC). Nitrocellulose supported the highest proportion of motile filaments (75%), while 47 - 61% of filaments were motile on other surfaces. Within the methacrylate polymers, average filament velocities increased with decreasing hydrophobicity of the surface. Distributions of instantaneous acceleration values and angle deviations suggested more erratic and stuttered movement on the methacrylates and polystyrene than on NC, in line with qualitative visual observations. Despite the higher velocities and high proportion of motile filaments on NC, this surface resulted in a high proportion of small filaments and high rates of filament breakage during motility. Similar effects were observed on PS and PtBMA, while PBMA and PMMA supported longer filaments with less observed breakage.

  5. The Evolution from Integration to Inclusion: The Hong Kong Tale

    ERIC Educational Resources Information Center

    Poon-McBrayer, Kim Fong

    2014-01-01

    As a worldwide movement, some forms or stages of inclusive education have been experimented and/or mandated in various countries since the mid-1970s. Integration was piloted in Hong Kong in 1997 and remains the official rhetoric and policy. Three developmental phases of inclusive education, namely, integration, integration in transition to…

  6. Inclusive Education in Italy: Description and Reflections on Full Inclusion

    ERIC Educational Resources Information Center

    Anastasiou, Dimitris; Kauffman, James M.; Di Nuovo, Santo

    2015-01-01

    Inclusion of students with disabilities when appropriate is an important goal of special education for students with special needs. Full inclusion, meaning no education for any child in a separate setting, is held to be desirable by some, and Italy is likely the nation with an education system most closely approximating full inclusion on the…

  7. Structures related to attachment and motility in the marine eugregarine Cephaloidophora cf. communis (Apicomplexa).

    PubMed

    Kováčiková, Magdaléna; Simdyanov, Timur G; Diakin, Andrei; Valigurová, Andrea

    2017-03-07

    Gregarines represent a highly diversified group of ancestral apicomplexans, with various modes of locomotion and host-parasite interactions. The eugregarine parasite of the barnacle Balanus balanus, Cephaloidophora cf. communis, exhibits interesting organisation of its attachment apparatus along with unique motility modes. The pellicle covered gregarine is arranged into longitudinal epicytic folds. The epimerite is separated from the protomerite by a septum consisting of tubulin-rich filamentous structures and both are packed with microneme-like structures suggestive of their function in the production of adhesives important for attachment and secreted through the abundant epimerite pores. Detached trophozoites and gamonts are capable of gliding motility, enriched by jumping and rotational movements with rapid changes in gliding direction and cell flexions. Actin in its polymerised form (F-actin) is distributed throughout the entire gregarine, while myosin, detected in the cortical region of the cell, follows the pattern of the epicytic folds. Various motility modes exhibited by individuals of C. cf. communis, together with significant changes in their cell shape during locomotion, are not concordant with the gliding mechanisms generally described in apicomplexan zoites and indicate that additional structures must be involved (e.g. two 12-nm filaments; the specific dentate appearance of internal lamina inside the epicytic folds).

  8. Shear-induced orientational dynamics and spatial heterogeneity in suspensions of motile phytoplankton.

    PubMed

    Barry, Michael T; Rusconi, Roberto; Guasto, Jeffrey S; Stocker, Roman

    2015-11-06

    Fluid flow, ubiquitous in natural and man-made environments, has the potential to profoundly impact the transport of microorganisms, including phytoplankton in aquatic habitats and bioreactors. Yet, the effect of ambient flow on the swimming behaviour of phytoplankton has remained poorly understood, largely owing to the difficulty of observing cell-flow interactions at the microscale. Here, we present microfluidic experiments where we tracked individual cells for four species of motile phytoplankton exposed to a spatially non-uniform fluid shear rate, characteristic of many flows in natural and artificial environments. We observed that medium-to-high mean shear rates (1-25 s(-1)) produce heterogeneous cell concentrations in the form of regions of accumulation and regions of depletion. The location of these regions relative to the flow depends on the cells' propulsion mechanism, body shape and flagellar arrangement, as captured by an effective aspect ratio. Species having a large effective aspect ratio accumulated in the high-shear regions, owing to shear-induced alignment of the swimming orientation with the fluid streamlines. Species having an effective aspect ratio close to unity exhibited little preferential accumulation at low-to-moderate flow rates, but strongly accumulated in the low-shear regions under high flow conditions, potentially owing to an active, behavioural response of cells to shear. These observations demonstrate that ambient fluid flow can strongly affect the motility and spatial distribution of phytoplankton and highlight the rich dynamics emerging from the interaction between motility, morphology and flow.

  9. Wild-type p53 controls cell motility and invasion by dual regulation of MET expression

    PubMed Central

    Hwang, Chang-Il; Matoso, Andres; Corney, David C.; Flesken-Nikitin, Andrea; Körner, Stefanie; Wang, Wei; Boccaccio, Carla; Thorgeirsson, Snorri S.; Comoglio, Paolo M.; Hermeking, Heiko; Nikitin, Alexander Yu.

    2011-01-01

    Recent observations suggest that p53 mutations are responsible not only for growth of primary tumors but also for their dissemination. However, mechanisms involved in p53-mediated control of cell motility and invasion remain poorly understood. By using the primary ovarian surface epithelium cell culture, we show that conditional inactivation of p53 or expression of its mutant forms results in overexpression of MET receptor tyrosine kinase, a crucial regulator of invasive growth. At the same time, cells acquire increased MET-dependent motility and invasion. Wild-type p53 negatively regulates MET expression by two mechanisms: (i) transactivation of MET-targeting miR-34, and (ii) inhibition of SP1 binding to MET promoter. Both mechanisms are not functional in p53 absence, but mutant p53 proteins retain partial MET promoter suppression. Accordingly, MET overexpression, cell motility, and invasion are particularly high in p53-null cells. These results identify MET as a critical effector of p53 and suggest that inhibition of MET may be an effective antimetastatic approach to treat cancers with p53 mutations. These results also show that the extent of advanced cancer traits, such as invasion, may be determined by alterations in individual components of p53/MET regulatory network. PMID:21831840

  10. Shear-induced orientational dynamics and spatial heterogeneity in suspensions of motile phytoplankton

    PubMed Central

    Barry, Michael T.; Rusconi, Roberto; Guasto, Jeffrey S.; Stocker, Roman

    2015-01-01

    Fluid flow, ubiquitous in natural and man-made environments, has the potential to profoundly impact the transport of microorganisms, including phytoplankton in aquatic habitats and bioreactors. Yet, the effect of ambient flow on the swimming behaviour of phytoplankton has remained poorly understood, largely owing to the difficulty of observing cell–flow interactions at the microscale. Here, we present microfluidic experiments where we tracked individual cells for four species of motile phytoplankton exposed to a spatially non-uniform fluid shear rate, characteristic of many flows in natural and artificial environments. We observed that medium-to-high mean shear rates (1–25 s−1) produce heterogeneous cell concentrations in the form of regions of accumulation and regions of depletion. The location of these regions relative to the flow depends on the cells' propulsion mechanism, body shape and flagellar arrangement, as captured by an effective aspect ratio. Species having a large effective aspect ratio accumulated in the high-shear regions, owing to shear-induced alignment of the swimming orientation with the fluid streamlines. Species having an effective aspect ratio close to unity exhibited little preferential accumulation at low-to-moderate flow rates, but strongly accumulated in the low-shear regions under high flow conditions, potentially owing to an active, behavioural response of cells to shear. These observations demonstrate that ambient fluid flow can strongly affect the motility and spatial distribution of phytoplankton and highlight the rich dynamics emerging from the interaction between motility, morphology and flow. PMID:26538558

  11. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility.

    PubMed

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-06-29

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility.

  12. Efficacy of aphrodisiac plants towards improvement in semen quality and motility in infertile males.

    PubMed

    Mahajan, Ghanashyam Keshav; Mahajan, Arun Yashwant; Mahajan, Raghunath Totaram

    2012-02-17

    Infertility is the inability to conceive after one year of unprotected intercourse. In the present study, herbal composition prepared by using medicinal plants having aphrodisiac potentials was administered orally to the albino rats for 40 days and to the oligospermic patients for 90 days in order to prove the efficacy of herbal composition. Herbal composition was the mixture (powder form) of the medicinal plants namely, Mucuna pruriens (Linn), Chlorophytum borivillianum (Sant and Fernand), and Eulophia campestris (Wall). In the neem oil treated albino rats, there was significant reduction in almost all the parameters viz. body weight, testes and epididymes weight, sperm density and motility, serum levels of testosterone, FSH, and LH compared with control rats. Treatment with said herbal composition for 40 days results significant increased in the body weight, testis, and epididymes weight in rats. Concomitantly the sperm motility and the sperm density were significantly increased. After 90 days of treatment with this herbal composition, sperm density vis-a-vis motility was increased in oligozoospermic patients as a result of elevation in serum testosterone levels. No side effects were noticed during the entire duration of the trial.

  13. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility

    PubMed Central

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-01-01

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility. PMID:27367677

  14. Inclusive Flavour Tagging Algorithm

    NASA Astrophysics Data System (ADS)

    Likhomanenko, Tatiana; Derkach, Denis; Rogozhnikov, Alex

    2016-10-01

    Identifying the flavour of neutral B mesons production is one of the most important components needed in the study of time-dependent CP violation. The harsh environment of the Large Hadron Collider makes it particularly hard to succeed in this task. We present an inclusive flavour-tagging algorithm as an upgrade of the algorithms currently used by the LHCb experiment. Specifically, a probabilistic model which efficiently combines information from reconstructed vertices and tracks using machine learning is proposed. The algorithm does not use information about underlying physics process. It reduces the dependence on the performance of lower level identification capacities and thus increases the overall performance. The proposed inclusive flavour-tagging algorithm is applicable to tag the flavour of B mesons in any proton-proton experiment.

  15. SUSCEPTIBILITY AND PROTECTIVE MECHANISMS OF MOTILE AND NON MOTILE CELLS OF HAEMATOCOCCUS PLUVIALIS (CHLOROPHYCEAE) TO PHOTOOXIDATIVE STRESS(1).

    PubMed

    Han, Danxiang; Wang, Junfeng; Sommerfeld, Milton; Hu, Qiang

    2012-06-01

    The life cycle of the unicellular green alga Haematococcus pluvialis consists of motile and nonmotile stages under typical growing conditions. In this study, we observed that motile cells were more susceptible than nonmotile cells to high light, resulting in a decrease in population density and photo-bleaching. Using two Haematococcus strains, CCAP 34/12 (a motile cell dominated strain) and SAG 34/1b (a nonmotile cell dominated strain), as model systems we investigated the cause of cell death and the protective mechanisms of the cells that survived high light. The death of motile cells under high light was attributed to the generation of excess reactive oxygen species (ROS), which caused severe damage to the photosynthetic components and the membrane system. Motile cells were able to dissipate excess light energy by nonphotochemical quenching and to relax ROS production by a partially up-regulated scavenging enzyme system. However, these strategies were not sufficient to protect the motile cells from high light stress. In contrast, nonmotile cells were able to cope with and survive under high light by (i) relaxing the over-reduced photosynthetic electron transport chain (PETC), thereby effectively utilizing PETC-generated NADPH to produce storage starch, neutral lipid, and astaxanthin, and thus preventing formation of excess ROS; (ii) down-regulating the linear electron transport by decreasing the level of cytochrome f; and (iii) consuming excess electrons produced by PSII via a significantly enhanced plastid terminal oxidase pathway.

  16. Making Inclusion Work

    ERIC Educational Resources Information Center

    Villa, Jennifer; Colker, Laura

    2006-01-01

    Inclusion is an oft-used buzzword in education. It is also a concept that the author highly values and wants to be a part of her teaching. She feels she would not be teaching to her potential if she was not able to reach all students. She truly wants a classroom in which all children have access. The author was a Sure Start teacher at a U.S.…

  17. miR-17 regulates melanoma cell motility by inhibiting the translation of ETV1.

    PubMed

    Cohen, Ronit; Greenberg, Eyal; Nemlich, Yael; Schachter, Jacob; Markel, Gal

    2015-08-07

    Melanoma is an aggressive malignancy with a high metastatic potential. microRNA-17 (miR-17) is a member of the oncogenic miR-17/92 cluster. Here we study the effect of miR-17 on melanoma cell motility. Over expression of the mature or pri-microRNA form of miR-17 in WM-266-4 and 624mel melanoma lines enhances cell motility, evident in both wound healing and transwell migration assays. TargetScan algorithm predicts the PEA3-subfamily member ETV1 as a direct target of miR-17. Indeed, a 3-4-fold decrease of ETV1 protein levels are observed following miR-17 transfection into the various melanoma lines, with no significant change in ETV1 mRNA expression. Dual luciferase experiments demonstrate direct binding of miR-17 to the 3'-untranslated region of ETV1, confirmed by abolishing point mutations in the putative binding site. These combined results suggest regulation of ETV1 by miR-17 by a direct translational repression. Further, in both melanoma cell lines ETV1 knockdown by selective siRNA successfully pheno-copies the facilitated cell migration, while overexpression of ETV1 inhibits cell motility and migration. Altered ETV1 expression does not affect melanoma net-proliferation. In conclusion, we show a new role for miR-17 in melanoma, facilitating cell motility, by targeting the translation of ETV1 protein, which may support the development of metastasis.

  18. Borrelia burgdorferi uniquely regulates its motility genes and has an intricate flagellar hook-basal body structure.

    PubMed

    Sal, Melanie S; Li, Chunhao; Motalab, M A; Shibata, Satoshi; Aizawa, Shin-ichi; Charon, Nyles W

    2008-03-01

    Borrelia burgdorferi is a flat-wave, motile spirochete that causes Lyme disease. Motility is provided by periplasmic flagella (PFs) located between the cell cylinder and an outer membrane sheath. The structure of these PFs, which are composed of a basal body, a hook, and a filament, is similar to the structure of flagella of other bacteria. To determine if hook formation influences flagellin gene transcription in B. burgdorferi, we inactivated the hook structural gene flgE by targeted mutagenesis. In many bacteria, completion of the hook structure serves as a checkpoint for transcriptional control of flagellum synthesis and other chemotaxis and motility genes. Specifically, the hook allows secretion of the anti-sigma factor FlgM and concomitant late gene transcription promoted by sigma28. However, the control of B. burgdorferi PF synthesis differs from the control of flagellum synthesis in other bacteria; the gene encoding sigma28 is not present in the genome of B. burgdorferi, nor are any sigma28 promoter recognition sequences associated with the motility genes. We found that B. burgdorferi flgE mutants lacked PFs, were rod shaped, and were nonmotile, which substantiates previous evidence that PFs are involved in both cell morphology and motility. Although most motility and chemotaxis gene products accumulated at wild-type levels in the absence of FlgE, mutant cells had markedly decreased levels of the flagellar filament proteins FlaA and FlaB. Further analyses showed that the reduction in the levels of flagellin proteins in the spirochetes lacking FlgE was mediated at the posttranscriptional level. Taken together, our results indicate that in B. burgdorferi, the completion of the hook does not serve as a checkpoint for transcriptional regulation of flagellum synthesis. In addition, we also present evidence that the hook protein in B. burgdorferi forms a high-molecular-weight complex and that formation of this complex occurs in the periplasmic space.

  19. Working through the Inclusion Maze.

    ERIC Educational Resources Information Center

    Henderson, Michelle

    1994-01-01

    Suggests that if inclusion programs are implemented correctly, students with special needs will begin to have more success stories, which will help educators find a pathway out of the dead ends of the inclusion maze. (RS)

  20. Inclusive Education for Children with Specific Learning Difficulties: Analysis of Opportunities and Barriers in Inclusive Education in Slovenia

    ERIC Educational Resources Information Center

    Kavkler, Marija; Babuder, Milena Košak; Magajna, Lidija

    2015-01-01

    Inclusive education allows for universal inclusion, participation and achievement of all children, including children with specific learning difficulties (SpLD). Children with SpLD form a heterogeneous group with diverse cognitive deficits, special educational needs (SEN) and strengths, and have a legislated right to the continuum of both…

  1. Do Melt Inclusions Answer Big Questions?

    NASA Astrophysics Data System (ADS)

    Hofmann, A. W.; Sobolev, A. V.

    2009-12-01

    In a pioneering paper, Sobolev and Shimizu (1993) demonstrated the existence of ultra-depleted melt inclusions in olivine phenocrysts in MORB. They interpreted these as evidence for the preservation of parental melts formed by progressive near-fractional melting. Subsequently many cases have been described where melt inclusions from single basalt samples display enormous chemical and isotopic heterogeneity. The interpretation of these observations hinges critically on whether such melt inclusions can faithfully preserve primary or parental melt composition. If they do, melt inclusion data can truly answer big questions from small-scale observations. If they do not, they answer rather small questions. Favoring the second possibility, Danyushevsky et al. (2004) have suggested that much of the observed variability of highly incompatible trace elements in melt inclusions “may not represent geologically significant melts, but instead reflect localized, grain-scale reaction processes within the magmatic plumbing system.” We disagree and show that this mechanism cannot, for example, explain isotopic heterogeneity measured in several suites of melt inclusions, nor does it not account for the presence of ultra-depleted melts and "ghost" plagioclase signatures in other inclusions. More recently, Spandler et al. (2007) have suggested on the basis of experimental evidence that diffusion rates for REE in olivine are so rapid that parental melt compositions in melt inclusions are rapidly falsified by diffusional exchange with (evolved) host lava. We show that the very fact that extreme chemical and isotopic heterogeneities are routinely preserved in melt inclusions demonstrates that this conclusion is unwarranted, either because residence times of the olivine phenocrysts are much shorter than assumed by Spandler et al. or because the high experimental diffusion rates are caused by an unknown experimental artifact. Although there is no obvious flaw in design and execution of

  2. A new titanium-bearing calcium aluminosilicate phase. 2: Crystallography and crystal chemistry of grains formed in slowly cooled melts with bulk compositions of calcium-aluminium-rich inclusions

    NASA Technical Reports Server (NTRS)

    Barber, David J.; Beckett, John R.; Paque, Julie M.; Stolper, Edward

    1994-01-01

    The crystallography and crystal chemistry of a new calcium- titanium-aluminosilicate mineral (UNK) observed in synthetic analogs to calcium-aluminum-rich inclusions (CAIs) from carbonaceous chondrites was studied by electron diffraction techniques. The unit cell is primitive hexagonal or trigonal, with a = 0.790 +/- 0.02 nm and c = 0.492 +/- 0.002 nm, similar to the lattice parameters of melilite and consistent with cell dimensions for crystals in a mixer furnace slag described by Barber and Agrell (1994). The phase frequently displays an epitactic relationship in which melilite acts as the host, with (0001)(sub UNK) parallel (001)(sub mel) and zone axis group 1 0 -1 0(sub UNK) parallel zone axis group 1 0 0(sub mel). If one of the two space groups determined by Barber and Agrell (1994) for their sample of UNK is applicable (P3m1 or P31m), then the structure is probably characterized by puckered sheets of octahedra and tetrahedra perpendicular to the c-axis with successive sheets coordinated by planar arrays of Ca. In this likely structure, each unit cell contains three Ca sites located in mirror planes, one octahedrally coordinated cation located along a three-fold axis and five tetrahedrally coordinated cations, three in mirrors and two along triads. The octahedron contains Ti but, because there are 1.3-1.9 cations of Ti/formula unit, some of the Ti must also be in tetrahedral coordination, an unusual but not unprecedented situation for a silicate. Tetrahedral sites in mirror planes would contain mostly Si, with lesser amounts of Al while those along the triads correspondingly contain mostly Al with subordinate Ti. The structural formula, therefore, can be expressed as Ca(sub 3)(sup VIII)(Ti,Al)(sup VI)(Al,Ti,Si)(sub 2)(sup IV)(Si,Al)(sub 3)(sup IV)O14 with Si + Ti = 4. Compositions of meteoritic and synthetic Ti-bearing samples of the phase can be described in terms of a binary solid solution between the end-members Ca3TiAl2Si3O14 and Ca3Ti(AlTi)(AlSi2)O14. A Ti

  3. Inclusions in freely suspended smectic films

    NASA Astrophysics Data System (ADS)

    Stannarius, Ralf; Harth, Kirsten

    Smectic liquid crystal phases have a unique property: Like soap solutions, they can form stable freely suspended films. Their aspect ratios can be larger than one million to one. Such films can serve as models for two-dimensional (2D) uids, with or without in-plane anisotropy. Solid or liquid inclusions trapped in these films by capillary forces can move in the film plane and interact with other inclusions, with film thickness gradients or the film boundaries, and even with the local orientation field. We describe preparation techniques to incorporate particles or droplets in thin smectic films, and optical observation methods. Several aspects make inclusions in freely suspended films interesting research objects: They provide rich information on capillary forces as well as surface and interfacial tensions, they can serve as platforms for hydrodynamic studies in 2D, and they may help to understand coalescence dynamics at the transition from 2D to 3D...

  4. Normalizing difference in inclusive teaching.

    PubMed

    Baglieri, Susan; Knopf, Janice H

    2004-01-01

    Inclusion practices and special education can be transformed by using a disability studies perspective, which constructs differences as natural, acceptable, and ordinary. Although inclusion is a moral imperative in promoting social justice, some inclusive practices continue to marginalize students with disabilities. A truly inclusive school reflects a democratic philosophy whereby all students are valued, educators normalize difference through differentiated instruction, and the school culture reflects an ethic of caring and community.

  5. Computational and Modeling Strategies for Cell Motility

    NASA Astrophysics Data System (ADS)

    Wang, Qi; Yang, Xiaofeng; Adalsteinsson, David; Elston, Timothy C.; Jacobson, Ken; Kapustina, Maryna; Forest, M. Gregory

    A predictive simulation of the dynamics of a living cell remains a fundamental modeling and computational challenge. The challenge does not even make sense unless one specifies the level of detail and the phenomena of interest, whether the focus is on near-equilibrium or strongly nonequilibrium behavior, and on localized, subcellular, or global cell behavior. Therefore, choices have to be made clear at the outset, ranging from distinguishing between prokaryotic and eukaryotic cells, specificity within each of these types, whether the cell is "normal," whether one wants to model mitosis, blebs, migration, division, deformation due to confined flow as with red blood cells, and the level of microscopic detail for any of these processes. The review article by Hoffman and Crocker [48] is both an excellent overview of cell mechanics and an inspiration for our approach. One might be interested, for example, in duplicating the intricate experimental details reported in [43]: "actin polymerization periodically builds a mechanical link, the lamellipodium, connecting myosin motors with the initiation of adhesion sites, suggesting that the major functions driving motility are coordinated by a biomechanical process," or to duplicate experimental evidence of traveling waves in cells recovering from actin depolymerization [42, 35]. Modeling studies of lamellipodial structure, protrusion, and retraction behavior range from early mechanistic models [84] to more recent deterministic [112, 97] and stochastic [51] approaches with significant biochemical and structural detail. Recent microscopic-macroscopic models and algorithms for cell blebbing have been developed by Young and Mitran [116], which update cytoskeletal microstructure via statistical sampling techniques together with fluid variables. Alternatively, whole cell compartment models (without spatial details) of oscillations in spreading cells have been proposed [35, 92, 109] which show positive and negative feedback

  6. Inclusion: A Guide for Educators.

    ERIC Educational Resources Information Center

    Stainback, Susan, Ed.; Stainback, William, Ed.

    This book discusses the inclusion of students with disabilities in general education classrooms and describes strategies that enhance the social success and educational achievement for all students. Section 1 provides an introduction to inclusion and contains the following chapters: "Rationale for Inclusive Schooling" (Anastasios Karagiannis and…

  7. Developing Inclusive Schools: A Guide.

    ERIC Educational Resources Information Center

    Hoskins, Barbara

    This workbook provides practical information for developing and implementing inclusive school programs through understanding the educator role, using effective problem-solving strategies, and developing a support network to meet the challenges of inclusion. Ten chapters cover the following topics: (1) effective inclusion (an analysis of the trend…

  8. Inclusive Education under Collectivistic Culture

    ERIC Educational Resources Information Center

    Futaba, Yasuko

    2016-01-01

    This paper addresses how inclusive education under collective culture is possible. Inclusive education, which more-or-less involves changing the current schools, has been denied, doubted or distorted by both policy-makers and practitioners of general and special education in Japan. Main reason for the setback in inclusive education can be…

  9. Inclusion bodies in Plesiomonas shigelloides.

    PubMed Central

    Pastian, M R; Bromel, M C

    1984-01-01

    Inclusion bodies were discovered in seven environmental isolates of Plesiomonas shigelloides and the P. shigelloides control (ATCC 14029). Differential staining indicated that the inclusion bodies may be composed of polyphosphates, and developmental stages of the bodies may occur. The inclusion bodies may be useful for rapid presumptive identification of this organism. Images PMID:6320723

  10. Inclusive Education in South Korea

    ERIC Educational Resources Information Center

    Kim, Yong-Wook

    2014-01-01

    The purpose of this paper is to examine the current implementation of inclusive education in South Korea and discuss its challenges. The history of special education is first described followed by an introduction to policies relevant to special and inclusive education. Next, a critical discussion of the state of inclusive education follows built…

  11. Inclusion polymerization of isoprene in deoxycholic acid

    NASA Astrophysics Data System (ADS)

    Cataldo, Franco; Ragni, Pietro; Rosati, Aldo; Ursini, Ornella

    2009-05-01

    The radiation-induced polymerization of isoprene was made on its inclusion (or clathrate) complex with deoxycholic acid (DOCA) at 150 and 300 kGy. The microstructure of the resulting polyisoprene (PIP) was studied by FTIR spectroscopy and found fully comparable to that of PIP prepared by emulsion polymerization by a free radical initiator. Thus, the 1,4-trans content was found to be 48% and that of 1,4-cis units was 28% of the polymer structure; the remaining are being 1,2 and 3,4 units. The PIP irregular microstructure was justified in terms of monomer dynamics inside the DOCA channels. PIP from inclusion polymerization is fully amorphous as studied by differential thermal analysis (DTA) in comparison to an authentic sample of trans-1,4-polyisoprene, which instead has a crystalline melting point of 71.5 °C. The inclusion complex of PIP with DOCA (PIP@DOCA) shows a DTA melting point of 194.4 °C, 12.4 °C higher than the melting point of pure DOCA. PIP isolated from inclusion polymerization from DOCA and its complex PIP@DOCA was studied also by thermogravimetry (TGA) and differential thermogravimetry (DTG). Isoprene does not form inclusion complexes with urea and thiourea. When irradiated with these two compounds it produces an oily PIP oligomer whose microstructure was found by FTIR spectroscopy analogous to that of PIP prepared by emulsion polymerization by a free radical initiator.

  12. Conjunctival biopsy in adult form galactosialidosis.

    PubMed Central

    Usui, T; Sawaguchi, S; Abe, H; Iwata, K; Oyanagi, K

    1993-01-01

    Conjunctival biopsy was performed in two siblings with adult-form galactosialidosis. Electron microscopically, several types of intracytoplasmic inclusion were observed in the fibroblasts in conjunctival stroma, lymphatic capillary endothelial cells, Schwann cells, and epithelial cells. Membrane-bound vesicles with fibrillogranular content were frequently observed, and occasional lamellar structures were noted in these inclusions. Dense granular inclusions and oil droplets were also seen. Dense granular inclusions have not been reported in this disease previously. Images PMID:8384473

  13. Attenuation of cell motility observed with high doses of sphingosine 1-phosphate or phosphorylated FTY720 involves RGS2 through its interactions with the receptor S1P.

    PubMed

    Kohno, Takayuki; Igarashi, Yasuyuki

    2008-07-01

    Sphingosine 1-phosphate (S1P) stimulation enhances cell motility via the G-protein coupled S1P receptor S1P1. This ligand-induced, receptor-mediated cell motility follows a typical bell-shaped dose-response curve, that is, stimulation with low concentrations of S1P enhances cell motility, whereas excess ligand stimulation does not enhance it. So far, the attenuation of the response at higher ligand concentrations has not been explained. We report here that S1P1 interacts with the regulator of G protein signaling (RGS)-2 protein, which is a GTPase-activating protein (GAP) for heterotrimeric G proteins, in a concentration dependent manner. The RGS2-S1P1 complex dissociated at higher ligand concentrations, yet it was unaffected at low concentrations, suggesting that the dissociated RGS2 is involved in the concurrent decrease of cell motility. In RGS2 knockdown cells, the decrease of cell motility induced by high ligand concentrations was rescued. S1P1 internalization was not implicated in the attenuation of the response. Similar results were observed upon stimulation with the phosphorylated form of FTY720 (FTYP), which is an S1P1 agonist. In conclusion, the suppressed response in cell motility induced by excess S1P or FTYP via S1P1 is regulated by RGS2 functioning through a mechanism that is independent of S1P1 internalization.

  14. Utility of wireless motility capsule and lactulose breath testing in the evaluation of patients with chronic functional bloating

    PubMed Central

    Triadafilopoulos, George

    2016-01-01

    Background The precise aetiology of chronic bloating remains poorly understood and underlying gastroparesis, small bowel bacterial overgrowth and colonic inertia may, individually or collectively, play a role. Aims In this retrospective cohort analysis of symptomatic patients with chronic persistent bloating, we determined the clinical utility of wireless motility capsule and lactulose breath test in further defining the underlying aetiology for functional bloating. Methods Consecutive patients with chronic bloating underwent clinical assessment, wireless motility capsule testing and lactulose breath testing using standard protocols. Results 52 patients qualified for inclusion in this analysis, fulfilling Rome III criteria for functional bloating. Most patients (54%) had an abnormal wireless motility capsule study; of those, 11.5% had evidence of gastroparesis, 7.7% had small bowel transit delay, 15.8% had colonic inertia, 3.8% had delayed gastric and small bowel transit, 5.6% had combined gastric and colonic transit delay, 3.8% had delayed small bowel and colonic transit, and 5.6% had delayed gastric, small bowel and colon transit times. Using clinical questionnaires the median scores for bloating, constipation and eructation were not significantly different. Neither constipation nor eructation was specific to gastroparesis or colonic inertia but bloating was numerically more prevalent and severe in patients with delayed small bowel transit. 40% of patients had positive lactulose breath test but had no distinguishing clinical characteristics. Conclusions Chronic functional bloating may reflect underlying gastroparesis, small intestinal bacterial overgrowth or colonic inertia. Wireless motility capsule and lactulose breath test are useful in the assessment of patients with bloating and should be considered during evaluation. PMID:27648298

  15. Geometry-Driven Polarity in Motile Amoeboid Cells.

    PubMed

    Nagel, Oliver; Guven, Can; Theves, Matthias; Driscoll, Meghan; Losert, Wolfgang; Beta, Carsten

    2014-01-01

    Motile eukaryotic cells, such as leukocytes, cancer cells, and amoeba, typically move inside the narrow interstitial spacings of tissue or soil. While most of our knowledge of actin-driven eukaryotic motility was obtained from cells that move on planar open surfaces, recent work has demonstrated that confinement can lead to strongly altered motile behavior. Here, we report experimental evidence that motile amoeboid cells undergo a spontaneous symmetry breaking in confined interstitial spaces. Inside narrow channels, the cells switch to a highly persistent, unidirectional mode of motion, moving at a constant speed along the channel. They remain in contact with the two opposing channel side walls and alternate protrusions of their leading edge near each wall. Their actin cytoskeleton exhibits a characteristic arrangement that is dominated by dense, stationary actin foci at the side walls, in conjunction with less dense dynamic regions at the leading edge. Our experimental findings can be explained based on an excitable network model that accounts for the confinement-induced symmetry breaking and correctly recovers the spatio-temporal pattern of protrusions at the leading edge. Since motile cells typically live in the narrow interstitial spacings of tissue or soil, we expect that the geometry-driven polarity we report here plays an important role for movement of cells in their natural environment.

  16. Neuropeptide Y inhibits interleukin-1 beta-induced microglia motility.

    PubMed

    Ferreira, Raquel; Santos, Tiago; Cortes, Luísa; Cochaud, Stéphanie; Agasse, Fabienne; Silva, Ana Paula; Xapelli, Sara; Malva, João O

    2012-01-01

    Increasing evidences suggest that neuropeptide Y (NPY) may act as a key modulator of the cross-talk between the brain and the immune system in health and disease. In the present study, we dissected the possible inhibitory role of NPY upon inflammation-associated microglial cell motility. NPY, through activation of Y(1) receptors, was found to inhibit lipopolysaccharide (LPS)-induced microglia (N9 cell line) motility. Moreover, stimulation of microglia with LPS was inhibited by IL-1 receptor antagonist (IL-1ra), suggesting the involvement of endogenous interleukin-1 beta (IL-1β) in this process. Direct stimulation with IL-1β promoted downstream p38 mitogen-activated protein kinase mobilization and increased microglia motility. Moreover, consistently, p38 mitogen-activated protein kinase inhibition decreased the extent of actin filament reorganization occurring during plasma membrane ruffling and p38 phosphorylation was inhibited by NPY, involving Y(1) receptors. Significantly, the key inhibitory role of NPY on LPS-induced motility of CD11b-positive cells was further confirmed in mouse brain cortex explants. In summary, we revealed a novel functional role for NPY in the regulation of microglial function that may have important implications in the modulation of CNS injuries/diseases where microglia migration/motility might play a role.

  17. Biomimetic systems for studying actin-based motility.

    PubMed

    Upadhyaya, Arpita; van Oudenaarden, Alexander

    2003-09-16

    Actin polymerization provides a major driving force for eukaryotic cell motility. Successive intercalation of monomeric actin subunits between the plasma membrane and the filamentous actin network results in protrusions of the membrane enabling the cell to move or to change shape. One of the challenges in understanding eukaryotic cell motility is to dissect the elementary biochemical and biophysical steps that link actin polymerization to mechanical force generation. Recently, significant progress was made using biomimetic, in vitro systems that are inspired by the actin-based motility of bacterial pathogens such as Listeria monocytogenes. Polystyrene microspheres and synthetic phospholipid vesicles coated with proteins that initiate actin polymerization display motile behavior similar to Listeria, mimicking the leading edge of lamellipodia and filopodia. A major advantage of these biomimetic systems is that both biochemical and physical parameters can be controlled precisely. These systems provide a test bed for validating theoretical models on force generation and polarity establishment resulting from actin polymerization. In this review, we discuss recent experimental progress using biomimetic systems propelled by actin polymerization and discuss these results in the light of recent theoretical models on actin-based motility.

  18. PACRG, a protein linked to ciliary motility, mediates cellular signaling.

    PubMed

    Loucks, Catrina M; Bialas, Nathan J; Dekkers, Martijn P J; Walker, Denise S; Grundy, Laura J; Li, Chunmei; Inglis, P Nick; Kida, Katarzyna; Schafer, William R; Blacque, Oliver E; Jansen, Gert; Leroux, Michel R

    2016-07-01

    Cilia are microtubule-based organelles that project from nearly all mammalian cell types. Motile cilia generate fluid flow, whereas nonmotile (primary) cilia are required for sensory physiology and modulate various signal transduction pathways. Here we investigate the nonmotile ciliary signaling roles of parkin coregulated gene (PACRG), a protein linked to ciliary motility. PACRG is associated with the protofilament ribbon, a structure believed to dictate the regular arrangement of motility-associated ciliary components. Roles for protofilament ribbon-associated proteins in nonmotile cilia and cellular signaling have not been investigated. We show that PACRG localizes to a small subset of nonmotile cilia in Caenorhabditis elegans, suggesting an evolutionary adaptation for mediating specific sensory/signaling functions. We find that it influences a learning behavior known as gustatory plasticity, in which it is functionally coupled to heterotrimeric G-protein signaling. We also demonstrate that PACRG promotes longevity in C. elegans by acting upstream of the lifespan-promoting FOXO transcription factor DAF-16 and likely upstream of insulin/IGF signaling. Our findings establish previously unrecognized sensory/signaling functions for PACRG and point to a role for this protein in promoting longevity. Furthermore, our work suggests additional ciliary motility-signaling connections, since EFHC1 (EF-hand containing 1), a potential PACRG interaction partner similarly associated with the protofilament ribbon and ciliary motility, also positively regulates lifespan.

  19. PACRG, a protein linked to ciliary motility, mediates cellular signaling

    PubMed Central

    Loucks, Catrina M.; Bialas, Nathan J.; Dekkers, Martijn P. J.; Walker, Denise S.; Grundy, Laura J.; Li, Chunmei; Inglis, P. Nick; Kida, Katarzyna; Schafer, William R.; Blacque, Oliver E.; Jansen, Gert; Leroux, Michel R.

    2016-01-01

    Cilia are microtubule-based organelles that project from nearly all mammalian cell types. Motile cilia generate fluid flow, whereas nonmotile (primary) cilia are required for sensory physiology and modulate various signal transduction pathways. Here we investigate the nonmotile ciliary signaling roles of parkin coregulated gene (PACRG), a protein linked to ciliary motility. PACRG is associated with the protofilament ribbon, a structure believed to dictate the regular arrangement of motility-associated ciliary components. Roles for protofilament ribbon–associated proteins in nonmotile cilia and cellular signaling have not been investigated. We show that PACRG localizes to a small subset of nonmotile cilia in Caenorhabditis elegans, suggesting an evolutionary adaptation for mediating specific sensory/signaling functions. We find that it influences a learning behavior known as gustatory plasticity, in which it is functionally coupled to heterotrimeric G-protein signaling. We also demonstrate that PACRG promotes longevity in C. elegans by acting upstream of the lifespan-promoting FOXO transcription factor DAF-16 and likely upstream of insulin/IGF signaling. Our findings establish previously unrecognized sensory/signaling functions for PACRG and point to a role for this protein in promoting longevity. Furthermore, our work suggests additional ciliary motility-signaling connections, since EFHC1 (EF-hand containing 1), a potential PACRG interaction partner similarly associated with the protofilament ribbon and ciliary motility, also positively regulates lifespan. PMID:27193298

  20. Sodium affects the sperm motility in the European eel.

    PubMed

    Vílchez, M Carmen; Morini, Marina; Peñaranda, David S; Gallego, Víctor; Asturiano, Juan F; Pérez, Luz

    2016-08-01

    The role of seminal plasma sodium and activation media sodium on sperm motility was examined by selectively removing the element from these two media, in European eel sperm. Sperm size (sperm head area) was also measured using an ASMA (Automated Sperm Morphometry Analyses) system, in the different conditions. Intracellular sodium [Na(+)]i was quantitatively analyzed by first time in the spermatozoa from a marine fish species. Measurement of [Na(+)]i was done before and after motility activation, by Flow Cytometry, using CoroNa Green AM as a dye. Sperm motility activation induced an increase in [Na(+)]i, from 96.72mM in quiescent stage to 152.21mM post-activation in seawater. A significant decrease in sperm head area was observed post-activation in seawater. There was a notable reduction in sperm motility when sodium was removed from the seminal plasma, but not when it was removed from the activation media. Sodium removal was also linked to a significant reduction in sperm head area in comparison to the controls. Our results indicate that the presence of the ion Na(+) in the seminal plasma (or in the extender medium) is necessary for the preservation of sperm motility in European eel, probably because it plays a role in maintaining an appropriate sperm cell volume in the quiescent stage of the spermatozoa.

  1. Bidirectional motility of the fission yeast kinesin-5, Cut7

    SciTech Connect

    Edamatsu, Masaki

    2014-03-28

    Highlights: • Motile properties of Cut7 (fission yeast kinesin-5) were studied for the first time. • Half-length Cut7 moved toward plus-end direction of microtubule. • Full-length Cut7 moved toward minus-end direction of microtubule. • N- and C-terminal microtubule binding sites did not switch the motile direction. - Abstract: Kinesin-5 is a homotetrameric motor with its motor domain at the N-terminus. Kinesin-5 crosslinks microtubules and functions in separating spindle poles during mitosis. In this study, the motile properties of Cut7, fission yeast kinesin-5, were examined for the first time. In in vitro motility assays, full-length Cut7 moved toward minus-end of microtubules, but the N-terminal half of Cut7 moved toward the opposite direction. Furthermore, additional truncated constructs lacking the N-terminal or C-terminal regions, but still contained the motor domain, did not switch the motile direction. These indicated that Cut7 was a bidirectional motor, and microtubule binding regions at the N-terminus and C-terminus were not involved in its directionality.

  2. 3D timelapse analysis of muscle satellite cell motility.

    PubMed

    Siegel, Ashley L; Atchison, Kevin; Fisher, Kevin E; Davis, George E; Cornelison, D D W

    2009-10-01

    Skeletal muscle repair and regeneration requires the activity of satellite cells, a population of myogenic stem cells scattered throughout the tissue and activated to proliferate and differentiate in response to myotrauma or disease. While it seems likely that satellite cells would need to navigate local muscle tissue to reach damaged areas, relatively little data on such motility exist, and most studies have been with immortalized cell lines. We find that primary satellite cells are significantly more motile than myoblast cell lines, and that adhesion to laminin promotes primary cell motility more than fourfold over other substrates. Using timelapse videomicroscopy to assess satellite cell motility on single living myofibers, we have identified a requirement for the laminin-binding integrin alpha 7 beta 1 in satellite cell motility, as well as a role for hepatocyte growth factor in promoting directional persistence. The extensive migratory behavior of satellite cells resident on muscle fibers suggests caution when determining, based on fixed specimens, whether adjacent cells are daughters from the same mother cell. We also observed more persistent long-term contact between individual satellite cells than has been previously supposed, potential cell-cell attractive and repulsive interactions, and migration between host myofibers. Based on such activity, we assayed for expression of "pathfinding" cues, and found that satellite cells express multiple guidance ligands and receptors. Together, these data suggest that satellite cell migration in vivo may be more extensive than currently thought, and could be regulated by combinations of signals, including adhesive haptotaxis, soluble factors, and guidance cues.

  3. Singing and social inclusion

    PubMed Central

    Welch, Graham F.; Himonides, Evangelos; Saunders, Jo; Papageorgi, Ioulia; Sarazin, Marc

    2014-01-01

    There is a growing body of neurological, cognitive, and social psychological research to suggest the possibility of positive transfer effects from structured musical engagement. In particular, there is evidence to suggest that engagement in musical activities may impact on social inclusion (sense of self and of being socially integrated). Tackling social exclusion and promoting social inclusion are common concerns internationally, such as in the UK and the EC, and there are many diverse Government ministries and agencies globally that see the arts in general and music in particular as a key means by which social needs can be addressed. As part of a wider evaluation of a national, Government-sponsored music education initiative for Primary-aged children in England (“Sing Up”), opportunity was taken by the authors, at the request of the funders, to assess any possible relationship between (a) children's developing singing behavior and development and (b) their social inclusion (sense of self and of being socially integrated). Subsequently, it was possible to match data from n = 6087 participants, drawn from the final 3 years of data collection (2008–2011), in terms of each child's individually assessed singing ability (based on their singing behavior of two well-known songs to create a “normalized singing score”) and their written responses to a specially-designed questionnaire that included a set of statements related to children's sense of being socially included to which the children indicated their level of agreement on a seven-point Likert scale. Data analyses suggested that the higher the normalized singing development rating, the more positive the child's self-concept and sense of being socially included, irrespective of singer age, sex and ethnicity. PMID:25120514

  4. Singing and social inclusion.

    PubMed

    Welch, Graham F; Himonides, Evangelos; Saunders, Jo; Papageorgi, Ioulia; Sarazin, Marc

    2014-01-01

    There is a growing body of neurological, cognitive, and social psychological research to suggest the possibility of positive transfer effects from structured musical engagement. In particular, there is evidence to suggest that engagement in musical activities may impact on social inclusion (sense of self and of being socially integrated). Tackling social exclusion and promoting social inclusion are common concerns internationally, such as in the UK and the EC, and there are many diverse Government ministries and agencies globally that see the arts in general and music in particular as a key means by which social needs can be addressed. As part of a wider evaluation of a national, Government-sponsored music education initiative for Primary-aged children in England ("Sing Up"), opportunity was taken by the authors, at the request of the funders, to assess any possible relationship between (a) children's developing singing behavior and development and (b) their social inclusion (sense of self and of being socially integrated). Subsequently, it was possible to match data from n = 6087 participants, drawn from the final 3 years of data collection (2008-2011), in terms of each child's individually assessed singing ability (based on their singing behavior of two well-known songs to create a "normalized singing score") and their written responses to a specially-designed questionnaire that included a set of statements related to children's sense of being socially included to which the children indicated their level of agreement on a seven-point Likert scale. Data analyses suggested that the higher the normalized singing development rating, the more positive the child's self-concept and sense of being socially included, irrespective of singer age, sex and ethnicity.

  5. Can We Build Inclusion?

    PubMed

    Kirkeby, Inge Mette; Grangaard, Sidse

    2016-01-01

    Inclusion of children with special needs in kindergartens and preschools may be approached from different angles. This paper raises the question of whether the physical framework of kindergartens makes any difference for daily life at the kindergarten at all, and whether it can support inclusion of some children with special needs. Hence the title - can we build inclusion? In the literature of Universal Design, accommodation and design features seldom reflect the less visible disabilities. The paper is based on a research project initiated to investigate how more or less space influences daily pedagogical practice in general. Twelve interviews were conducted with experienced teachers from twelve different kindergartens with different amounts of space, varying from a ratio of 2.1 m2 play area per child to 5.5 m2. The results indicated that, for a group of children with special needs in particular, the amount of space is crucial. This group consisted of children who were socially very extrovert, and who maybe were noisy, easily provoked, and quick to get involved in arguments with other children. Alternatively, children in the group were very restrained and withdrawn in social interaction. Based on the answers in the interviews, we found support for answering the question in the title in the affirmative; we can build inclusion! This is because the teachers' experience indicated that, if there was sufficient space per child, there were fewer conflicts and the children managed to stay in the same activity for a much longer period. Sufficient space made it possible to divide the children into smaller groups, and use any secluded space. Therefore, it was much easier for other children to include some children with special needs. Accordingly, we can say that, sufficient space per child and an adequate layout and furnishing of the kindergarten is an advantage for all children. This is a clear example of Universal Design in which architectural

  6. Paxillin controls directional cell motility in response to physical cues.

    PubMed

    Sero, Julia E; German, Alexandra E; Mammoto, Akiko; Ingber, Donald E

    2012-01-01

    Physical cues from the extracellular environment that influence cell shape and directional migration are transduced into changes in cytoskeletal organization and biochemistry through integrin-based cell adhesions to extracellular matrix (ECM). Paxillin is a focal adhesion (FA) scaffold protein that mediates integrin anchorage to the cytoskeleton, and has been implicated in regulation of FA assembly and cell migration. To determine whether paxillin is involved in coupling mechanical distortion with directional movement, cell shape was physically constrained by culturing cells on square-shaped fibronectin-coated adhesive islands surrounded by non-adhesive barrier regions that were created with a microcontact printing technique. Square-shaped cells preferentially formed FAs and extended lamellipodia from their corner regions when stimulated with PDGF, and loss of paxillin resulted in loss of this polarized response. Selective expression of the N- and C-terminal domains of paxillin produced opposite, but complementary, effects on suppressing or promoting lamellipodia formation in different regions of square cells, which corresponded to directional motility defects in vitro. Paxillin loss or mutation was also shown to affect the formation of circular dorsal ruffles, and this corresponded to changes in cell invasive behavior in 3D. This commentary addresses the implications of these findings in terms of how a multifunctional FA scaffold protein can link physical cues to cell adhesion, protrusion and membrane trafficking so as to control directional migration in 2D and 3D. We also discuss how microengineered ECM islands and in vivo model systems can be used to further elucidate the functions of paxillin in directional migration.

  7. Emergence of macroscopic directed motion in populations of motile colloids

    NASA Astrophysics Data System (ADS)

    Bricard, Antoine; Caussin, Jean-Baptiste; Desreumaux, Nicolas; Dauchot, Olivier; Bartolo, Denis

    2013-11-01

    From the formation of animal flocks to the emergence of coordinated motion in bacterial swarms, populations of motile organisms at all scales display coherent collective motion. This consistent behaviour strongly contrasts with the difference in communication abilities between the individuals. On the basis of this universal feature, it has been proposed that alignment rules at the individual level could solely account for the emergence of unidirectional motion at the group level. This hypothesis has been supported by agent-based simulations. However, more complex collective behaviours have been systematically found in experiments, including the formation of vortices, fluctuating swarms, clustering and swirling. All these (living and man-made) model systems (bacteria, biofilaments and molecular motors, shaken grains and reactive colloids) predominantly rely on actual collisions to generate collective motion. As a result, the potential local alignment rules are entangled with more complex, and often unknown, interactions. The large-scale behaviour of the populations therefore strongly depends on these uncontrolled microscopic couplings, which are extremely challenging to measure and describe theoretically. Here we report that dilute populations of millions of colloidal rolling particles self-organize to achieve coherent motion in a unique direction, with very few density and velocity fluctuations. Quantitatively identifying the microscopic interactions between the rollers allows a theoretical description of this polar-liquid state. Comparison of the theory with experiment suggests that hydrodynamic interactions promote the emergence of collective motion either in the form of a single macroscopic `flock', at low densities, or in that of a homogenous polar phase, at higher densities. Furthermore, hydrodynamics protects the polar-liquid state from the giant density fluctuations that were hitherto considered the hallmark of populations of self-propelled particles. Our

  8. Gliding Motility of Mycoplasma mobile on Uniform Oligosaccharides

    PubMed Central

    Kasai, Taishi; Hamaguchi, Tasuku

    2015-01-01

    ABSTRACT The binding and gliding of Mycoplasma mobile on a plastic plate covered by 53 uniform oligosaccharides were analyzed. Mycoplasmas bound to and glided on only 21 of the fixed sialylated oligosaccharides (SOs), showing that sialic acid is essential as the binding target. The affinities were mostly consistent with our previous results on the inhibitory effects of free SOs and suggested that M. mobile recognizes SOs from the nonreducing end with four continuous sites as follows. (i and ii) A sialic acid at the nonreducing end is tightly recognized by tandemly connected two sites. (iii) The third site is recognized by a loose groove that may be affected by branches. (iv) The fourth site is recognized by a large groove that may be enhanced by branches, especially those with a negative charge. The cells glided on uniform SOs in manners apparently similar to those of the gliding on mixed SOs. The gliding speed was related inversely to the mycoplasma's affinity for SO, suggesting that the detaching step may be one of the speed determinants. The cells glided faster and with smaller fluctuations on the uniform SOs than on the mixtures, suggesting that the drag caused by the variation in SOs influences gliding behaviors. IMPORTANCE Mycoplasma is a group of bacteria generally parasitic to animals and plants. Some Mycoplasma species form a protrusion at a pole, bind to solid surfaces, and glide in the direction of the protrusion. These procedures are essential for parasitism. Usually, mycoplasmas glide on mixed sialylated oligosaccharides (SOs) derived from glycoprotein and glycolipid. Since gliding motility on uniform oligosaccharides has never been observed, this study gives critical information about recognition and interaction between receptors and SOs. PMID:26148712

  9. Egg jelly proteins stimulate directed motility in Xenopus laevis sperm.

    PubMed

    Burnett, Lindsey A; Sugiyama, Hitoshi; Bieber, Allan L; Chandler, Douglas E

    2011-06-01

    Previously we have shown that extracts from Xenopus egg jelly (egg water) increase the passage of sperm through a porous membrane in a dose-dependent manner. Although this assay has shown that sperm accumulation occurs only in the presence of an egg water gradient, it has not revealed the dynamic features of how Xenopus sperm swim in such gradients. Here, we use video microscopic observations to trace sperm trajectories in a Zigmond chamber. Our results show that Xenopus sperm swim in linear and gently curving paths and only infrequently perform turns. In the presence of an egg water gradient, however, the percent of sperm swimming up the gradient axis and the net distance traveled by each sperm along this axis was increased significantly. There was no change in curvilinear velocity. Rather, the orientation of sperm travel was shifted to more closely match that of the gradient axis. In addition, using a porous filter assay, we demonstrate that the egg water protein allurin, in both purified and recombinant forms, stimulates directed motility of sperm. Finally, we use Oregon Green 488-conjugated allurin to show that this protein binds primarily to the sperm midpiece; binding of allurin to the entire head was observed in a minor subpopulation of sperm. Dose dependence of allurin binding occurred over the 0-1 µg/ml range and correlated well with previously published dose-dependent sperm attraction data. Binding was rapid with a half-time of about 10 sec. These data suggest that egg water proteins bind to sperm and modify sperm-orienting behavior.

  10. Mediation of muscular control of rhinarial motility in rats by the nasal cartilaginous skeleton

    PubMed Central

    Haidarliu, Sebastian; Kleinfeld, David; Ahissar, Ehud

    2014-01-01

    The Rhinarium is the rostral-most area of the snout that surrounds the nostrils, and is hairless in most mammals. In rodents, it participates in coordinated behaviors, active tactile sensing, and active olfactory sensing. In rats, the Rhinarium is firmly connected to the nasal cartilages, and its motility is determined by movements of the rostral end of the nasal cartilaginous skeleton. Here we demonstrate the nature of different cartilaginous regions that form the Rhinarium and the nasofacial muscles that deform these regions during movements of the nasal cartilaginous skeleton. These muscles, together with the dorsal nasal cartilage that was described here, function as a rhinarial motor plant. PMID:24249396

  11. Bacteria rolling: motilities of rosette colonies in Caulobacter crescentus

    NASA Astrophysics Data System (ADS)

    Zeng, Yu; Liu, Bin

    2016-11-01

    The aquatic bacterium Caulobacter crescentus has two life cycle stages with distinct motilities: freely swimming swarmer cells and immotile stalked cells. Here, we show a new type of movement performed by freely suspended rosettes, spontaneous aggregates of stalked cells aligned radially relative to each other. Reproductive rosette members generate predivisional daughter cells with flagella, inducing rotations of the rosette as a whole. Such rotations exhibit dynamic angular velocities and lead to intermittent linear movements along liquid-solid interfaces, resembling rolling movements. We reconstructed the translational and rotational dynamics of the rosette movements from high-speed filming and long-term tracking. A mechanical model was developed to explain the hydrodynamic mechanism underlying such motilities. Our study illustrated a nontrivial mechanism for clustered bacteria to achieve motilities and sheds light on the adaptive significance of the collective behaviors of microorganisms in complex fluid environments.

  12. Highly sensitive kinesin-microtubule motility assays using SLIM

    NASA Astrophysics Data System (ADS)

    Kandel, Mikhail; Teng, Kai Wen; Selvin, Paul R.; Popescu, Gabriel

    2016-03-01

    We provide an experimental demonstration of Spatial Light Interference Microscopy (SLIM) as a tool for measuring the motion of 25 nm tubulin structures without the use of florescence labels. Compared to intensity imaging methods such as phase contrast or DIC, our imaging technique relies on the ratios of images associated with optically introduced phase shifts, thus implicitly removing background illumination. To demonstrate our new found capabilities, we characterize kinesin-based motility continuously over periods of time where fluorescence would typically photobleach. We exploit this new method to compare the motility of microtubules at low ATP concentrations, with and without the tagging proteins formerly required to perform these studies. Our preliminary results show that the tags have a non-negligible effect on the microtubule motility, slowing the process down by more than 10%.

  13. Symbolic dynamics of jejunal motility in the irritable bowel

    NASA Astrophysics Data System (ADS)

    Wackerbauer, Renate; Schmidt, Thomas

    1999-09-01

    Different studies of the irritable bowel syndrome (IBS) by conventional analysis of jejunal motility report conflicting results. Therefore, our aim is to quantify the jejunal contraction activity by symbolic dynamics in order to discriminate between IBS and control subjects. Contraction amplitudes during fasting motility (phase II) are analyzed for 30 IBS and 30 healthy subjects. On the basis of a particular scale-independent discretization of the contraction amplitudes with respect to the median, IBS patients are characterized by increased block entropy as well as increased mean contraction amplitude. In a further more elementary level of analysis these differences can be reduced to specific contraction patterns within the time series, namely the fact that successive large contraction amplitudes are less ordered in IBS than in controls. These significant differences in jejunal motility may point to an altered control of the gut in IBS, although further studies on a representative number of patients have to be done for a validation of these findings.

  14. Autocrine motility factor modulates EGF-mediated invasion signaling

    PubMed Central

    Kho, Dhong Hyo; Zhang, Tianpeng; Balan, Vitaly; Yi, Wang; Ha, Seung-Wook; Xie, Youming; Raz, Avraham

    2014-01-01

    Autocrine motility factor (AMF) enhances invasion by breast cancer cells, but how its secretion and effector signaling are controlled in the tumor microenvironment is not fully understood. In this study, we investigated these issues with a chimeric AMF that is secreted at high levels through a canonical ER/Golgi pathway. Using this tool, we found that AMF enhances tumor cell motility by activating AKT/ERK, altering actin organization and stimulating β-catenin/TCF and AP-1 transcription. EGF enhanced secretion of AMF through its casein kinase 2-mediated phosphorylation. RNAi-mediated attenuation of AMF expression inhibited EGF-induced invasion by suppressing ERK signaling. Conversely, exogenous AMF overcame the inhibitory effect of EGFR inhibitor gefitinib on invasive motility by activating HER2 signaling. Taken together, our findings show how AMF modulates EGF-induced invasion while affecting acquired resistance to cytotoxic drugs in the tumor microenvironment. PMID:24576828

  15. Primary esophageal motility disorders (concise review for clinicians).

    PubMed

    Simić, A; Raznatović, Z; Skrobić, O; Pesko, P

    2006-01-01

    Primary esophageal motility disorders comprise various abnormal manometric patterns which usually present with dysphagia or chest pain. Some, such as achalasia, are diseases with a well defined pathology, characteristic manometric features, and good response to treatments directed towards the palliation of symptoms. Other disorders, such as diffuse esophageal spasm and nutcracker esophagus, have no well defined pathology and could represent a range of motility abnormalities associated with subtle neuropathic changes, gastresophageal reflux and anxiety states. On the other hand, hypocontracting esophagus is generally caused by weak musculature commonly associated with gastresophageal reflux disease. Although manometric patterns have been defined for these disorders, the relation with symptoms is poorly defined and in some cases the response to medical or surgical therapy unpredictable. The aim of this paper is to present a wide spectrum of the primary esophageal motility disorders, as well as to give a concise review for the clinicians encountering these specific diseases.

  16. Inclusive fitness in agriculture

    PubMed Central

    Kiers, E. Toby; Denison, R. Ford

    2014-01-01

    Trade-offs between individual fitness and the collective performance of crop and below-ground symbiont communities are common in agriculture. Plant competitiveness for light and soil resources is key to individual fitness, but higher investments in stems and roots by a plant community to compete for those resources ultimately reduce crop yields. Similarly, rhizobia and mycorrhizal fungi may increase their individual fitness by diverting resources to their own reproduction, even if they could have benefited collectively by providing their shared crop host with more nitrogen and phosphorus, respectively. Past selection for inclusive fitness (benefits to others, weighted by their relatedness) is unlikely to have favoured community performance over individual fitness. The limited evidence for kin recognition in plants and microbes changes this conclusion only slightly. We therefore argue that there is still ample opportunity for human-imposed selection to improve cooperation among crop plants and their symbionts so that they use limited resources more efficiently. This evolutionarily informed approach will require a better understanding of how interactions among crops, and interactions with their symbionts, affected their inclusive fitness in the past and what that implies for current interactions. PMID:24686938

  17. Genome-Wide Screening of Genes Required for Swarming Motility in Escherichia coli K-12▿ †

    PubMed Central

    Inoue, Tetsuyoshi; Shingaki, Ryuji; Hirose, Shotaro; Waki, Kaori; Mori, Hirotada; Fukui, Kazuhiro

    2007-01-01

    Escherichia coli K-12 has the ability to migrate on semisolid media by means of swarming motility. A systematic and comprehensive collection of gene-disrupted E. coli K-12 mutants (the Keio collection) was used to identify the genes involved in the swarming motility of this bacterium. Of the 3,985 nonessential gene mutants, 294 were found to exhibit a strongly repressed-swarming phenotype. Further, 216 of the 294 mutants displayed no significant defects in swimming motility; therefore, the 216 genes were considered to be specifically associated with the swarming phenotype. The swarming-associated genes were classified into various functional categories, indicating that swarming is a specialized form of motility that requires a wide variety of cellular activities. These genes include genes for tricarboxylic acid cycle and glucose metabolism, iron acquisition, chaperones and protein-folding catalysts, signal transduction, and biosynthesis of cell surface components, such as lipopolysaccharide, the enterobacterial common antigen, and type 1 fimbriae. Lipopolysaccharide and the enterobacterial common antigen may be important surface-acting components that contribute to the reduction of surface tension, thereby facilitating the swarm migration in the E. coli K-12 strain. PMID:17122336

  18. Effect of an acute intraluminal administration of capsaicin on oesophageal motor pattern in GORD patients with ineffective oesophageal motility.

    PubMed

    Grossi, L; Cappello, G; Marzio, L

    2006-08-01

    Ineffective oesophageal motility (IOM) is a functional disorder affecting about 50% of gastro-oesophageal reflux disease (GORD) patients. This disease in a severe form limits the clearing ability of the oesophagus and is considered one of the predictive factors for poorer GORD resolution. Capsaicin, the active compound of red pepper, exerts a prokinetic effect on oesophageal motility in healthy subjects by increasing the amplitude of body waves, even if no evidence exists on its possible role in situations of reduced motility. The aim of the study was to evaluate the effect of an acute administration of capsaicin on the oesophageal motor pattern in a group of GORD patients affected by severe IOM. Twelve GORD patients with severe IOM received an intra-oesophageal administration of 2 mL of a red pepper-olive oil mixture and 2 mL of olive oil alone serving as a control during a stationary manometry. The motor patterns of the oesophageal body and lower oesophageal sphincter (LOS) were analysed at baseline and after the infusion of the two stimuli. The administration of capsaicin induced a significant improvement in oesophageal body contractility when compared with baseline. The velocity of propagation of waves and the LOS basal tone remained unchanged. The motor pattern was unaltered by the administration of olive oil alone. An acute administration of capsaicin seems to improve the motor performance of the oesophageal body in patients with ineffective motility. Whether this could represent the basis for further therapeutic approaches of GORD patients needs further study.

  19. Cell motility and antibiotic tolerance of bacterial swarms

    NASA Astrophysics Data System (ADS)

    Zuo, Wenlong

    Many bacteria species can move across moist surfaces in a coordinated manner known as swarming. It is reported that swarm cells show higher tolerance to a wide variety of antibiotics than planktonic cells. We used the model bacterium E. coli to study how motility affects the antibiotic tolerance of swarm cells. Our results provide new insights for the control of pathogenic invasion via regulating cell motility. Mailing address: Room 306 Science Centre North Block, The Chinese University of Hong Kong, Shatin, N.T. Hong Kong SAR. Phone: +852-3943-6354. Fax: +852-2603-5204. E-mail: zwlong@live.com.

  20. Unidirecetional motility of excherichia coli in restrictive capillaries

    SciTech Connect

    Liu, Z.; Papadopoulos, K.D.

    1995-10-01

    In a 6-{mu}m capillary filled with buffer and in the absence of any chemotactic stimuli, Escherichia coli K-12 cells swim persistently in only one direction. This behavior of E. coli can be simply explained by means of the length and relative rigidity of their flagella. Single-cell motility parameters-swimming speed, turn angle, and run length time-were measured. Compared with the motility parameters measured in bulk phase, turn angle was influenced because of the effect of the geometrical restriction. 30 refs., 6 figs.

  1. Polymorphonuclear leucocyte motility in men with ankylosing spondylitis.

    PubMed Central

    Pease, C T; Fennell, M; Brewerton, D A

    1989-01-01

    The polymorphonuclear leucocyte (PMN) response to a chemotactic or chemokinetic stimulus is enhanced in men with ankylosing spondylitis (AS). This effect does not parallel the severity of disease activity or the size of the acute phase response, and it is independent of non-steroidal anti-inflammatory drug treatment. Polymorph function is normal in HLA-B27 positive brothers of probands with AS and in other HLA-B27 positive individuals in the absence of disease. Polymorph motility is also normal in patients with psoriasis vulgaris or Crohn's disease, indicating that enhanced PMN motility is not a non-specific consequence of all inflammatory disorders. PMID:2784306

  2. Enhanced motility of a microswimmer in rigid and elastic confinement.

    PubMed

    Ledesma-Aguilar, Rodrigo; Yeomans, Julia M

    2013-09-27

    We analyze the effect of confining rigid and elastic boundaries on the motility of a model dipolar microswimmer. Flexible boundaries are deformed by the velocity field of the swimmer in such a way that the motility of both extensile and contractile swimmers is enhanced. The magnitude of the increase in swimming velocity is controlled by the ratio of the swimmer-advection and elastic time scales, and the dipole moment of the swimmer. We explain our results by considering swimming between inclined rigid boundaries.

  3. Enhanced Motility of a Microswimmer in Rigid and Elastic Confinement

    NASA Astrophysics Data System (ADS)

    Ledesma-Aguilar, Rodrigo; Yeomans, Julia M.

    2013-09-01

    We analyze the effect of confining rigid and elastic boundaries on the motility of a model dipolar microswimmer. Flexible boundaries are deformed by the velocity field of the swimmer in such a way that the motility of both extensile and contractile swimmers is enhanced. The magnitude of the increase in swimming velocity is controlled by the ratio of the swimmer-advection and elastic time scales, and the dipole moment of the swimmer. We explain our results by considering swimming between inclined rigid boundaries.

  4. Secondary structure characterization of beta-lactamase inclusion bodies.

    PubMed

    Przybycien, T M; Dunn, J P; Valax, P; Georgiou, G

    1994-01-01

    The secondary structure of proteins in E. coli inclusion bodies was investigated via Raman spectroscopy. Inclusion bodies were purified from cells expressing different forms of RTEM beta-lactamase and grown at either 37 or 42 degrees C. All of the solid phase inclusion body samples examined gave amide I band spectra that were perturbed from that of the native, purified protein in both solution and powder forms; secondary structure estimates indicated significant decreases in alpha-helix and increases in beta-sheet contents in the inclusion body samples. The structure estimates for inclusion bodies isolated from 37 degrees C cultures were similar, regardless of aggregate localization in the E. coli cytoplasmic or periplasmic spaces or beta-lactamase precursor content. Inclusion bodies obtained from 42 degrees C cells exhibited a further reduction of alpha-helix and augmentation of beta-sheet contents relative to those from 37 degrees C cultures. These results are consistent with the paradigm for inclusion body formation via the self-association of intra-cellular folding intermediates having extensive secondary structure content. Further, the overall secondary structure content of inclusion bodies is not significantly affected by subcellular compartmentalization, but may be altered at increased temperatures.

  5. Preparing Teachers for Inclusive Education: Using Inclusive Pedagogy to Enhance Teaching and Learning for All

    ERIC Educational Resources Information Center

    Florian, Lani; Linklater, Holly

    2010-01-01

    As the concept of "inclusive education" has gained currency, students who would previously have been referred to specialist forms of provision, having been judged "less able", are now believed to belong in mainstream classrooms. However, it is often argued that teachers lack the necessary knowledge and skills to work with such students in…

  6. Regulation of vesicle transport and cell motility by Golgi-localized Dbs

    PubMed Central

    Fitzpatrick, Ethan R; Hu, Tinghui; Ciccarelli, Bryan T; Whitehead, Ian P

    2014-01-01

    DBS/MCF2L has been recently identified as a risk locus for osteoarthritis. It encodes a guanine nucleotide exchange factor (Dbs) that has been shown to regulate both normal and tumor cell motility. In the current study, we have determined that endogenous Dbs is predominantly expressed as 2 isoforms, a 130 kDa form (Dbs-130) that is localized to the Golgi complex, and an 80 kDa form (Dbs-80) that is localized to the endoplasmic reticulum (ER). We have previously described an inhibitor that binds to the RhoGEF domain of Dbs and blocks its transforming activity. Here we show that the inhibitor localizes to the Golgi, where it specifically interacts with Dbs-130. Inhibition of endogenous Dbs-130 activity is associated with reduced levels of activated Cdc42, enlarged Golgi, and resistance to Brefeldin A-mediated Golgi dispersal, suggesting a role for Dbs in vesicle transport. Cells treated with the inhibitor exhibit normal protein transport from the ER to the Golgi, but are defective in transport from the Golgi to the plasma membrane. Inhibition of Dbs-130 in MDA-MB-231 human breast tumor cells limits motility in both transwell and wound healing assays, but appears to have no effect on the organization of the microtubule cytoskeleton. The reduced motility is associated with a failure to reorient the Golgi toward the leading edge. This is consistent with the Golgi localization, and suggests that the Dbs-130 regulates aspects of the secretory pathway that are required to support cell polarization during directed migration. PMID:25483302

  7. Inclusive Jets in PHP

    NASA Astrophysics Data System (ADS)

    Roloff, P.

    Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

  8. Kruger strict morphology and post-thaw progressive motility in cryopreserved human spermatozoa.

    PubMed

    Lee, C-Y; Lee, C-T; Wu, C-H; Hsu, C-S; Hsu, M-I

    2012-05-01

    The purpose of this prospective study was to evaluate Kruger strict morphology and conventional semen analysis in predicting cryosurvival and the progressive motility recovery rate of frozen spermatozoa. Our study included 56 semen samples with >10 million spermatozoa per ejaculate. The main outcome measures were conventional semen analysis, strict morphology analysis by the Kruger method, cryosurvival rate and post-thaw sperm motility. A significant reduction in sperm motility after cryopreservation was demonstrated. The freeze-thawing process caused a 66% reduction in rapid progressive motile spermatozoa, a 45% reduction in slow progressive motile spermatozoa and a 2% reduction in nonprogressive motile spermatozoa. The cryosurvival and progressive motility recovery rates were not correlated with parameters of conventional semen analysis, such as sperm concentration, motility, WHO morphology and total motile count, but the progressive motility recovery rate was significantly correlated with the percentage of spermatozoa exhibiting Kruger normal morphology (P = 0.028). The recovery rate of rapidly progressive motility was profoundly decreased compared with slow progressive motility following the frozen-thaw procedure of semen. Kruger strict morphology assessment was a better predictor of the progressive motility recovery rate following the freezing-thaw procedure than parameters of conventional semen analysis.

  9. RHAMM, a receptor for hyaluronan-mediated motility, on normal human lymphocytes, thymocytes and malignant B cells: a mediator in B cell malignancy?

    PubMed

    Pilarski, L M; Masellis-Smith, A; Belch, A R; Yang, B; Savani, R C; Turley, E A

    1994-08-01

    RHAMM (Receptor for HA Mediated Motility) is a novel HA receptor that has been linked to regulating cell locomotion and density dependent contact inhibition of fibroblasts, smooth muscle cells, macrophages, lymphocytes, astrocytes and sperm. The ubiquitous expression of RHAMM suggests the existence of multiple isoforms, and indeed, RHAMM is found in various cellular compartments, namely nuclear, cytosolic, membrane-bound and extracellular. In this review, we emphasize the evolving role of RHAMM in B cell malignancies, and examine the function of RHAMM in T cell development in the thymic microenvironment. Both the motile behaviour of progenitor thymocytes (CD3-CD4-CD8-) and malignant B cells from multiple myeloma (MM), plasma cell leukemia, and hairy cell leukemia was blocked by monoclonal antibodies to RHAMM, suggesting that motility may correlate with increased expression of RHAMM at the cell surface. Interestingly, the soluble form of RHAMM is able to inhibit fibroblast locomotion, and it is likely that a balance between expression of both forms determines, in part the motility of cells. RHAMM appears to play a fundamental role in the immune system and the ability of RHAMM to function as a motility receptor is likely to be due to complex variables including the extent to which soluble RHAMM is secreted. RHAMM expression characterizes circulating monoclonal B cells as abnormal. potentially invasive and/or metastatic components of myeloma and may underlie the malignant behavior of these cells.

  10. Basic features of slime mould motility

    NASA Astrophysics Data System (ADS)

    Shirakawa, Tomohiro

    2015-03-01

    The plasmodium of Physarum polycephalum is a unicellular and multi-nuclear giant amoeba that is formed by fusions of myriads of uninucleate microscopic amoebae at a point in the life cycle of the organism. The very large unicellular form of the plasmodium is very uncommon in nature; on the contrary, almost all of the other higher organisms have multi-cellular bodies. Therefore, the plasmodium has an exceptional property: although the plasmodium is a unicellular organism, the size of the amoeba is variable. The smallest plasmodium consists of the fusion of two amoebae, so the smallest size is twice that of a usual amoeba. There is no upper limit to the largest size of the plasmodium, in principle. There is a record of very large plasmodium of more than a few metres. A more interesting point is that despite the variety in the size, the plasmodium can move, feed and form complex structures and adapt itself to the environment in an intelligent manner...

  11. SIRT1 inhibits the mouse intestinal motility and epithelial proliferation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    SIRT1 inhibits the mouse intestinal motility and epithelial proliferation. Sirtuin 1 (SIRT1), a NAD+-dependent histone deacetylase, is involved in a wide array of cellular processes, including glucose homeostasis, energy metabolism, proliferation and apoptosis, and immune response. However, it is un...

  12. Coherent motility measurements of biological objects in a large volume

    NASA Astrophysics Data System (ADS)

    Ebersberger, J.; Weigelt, G.; Li, Yajun

    1986-05-01

    We have performed space-time intensity cross-correlation measurements of boiling image plane speckle interferograms to investigate the motility of a large number of small biological objects. Experiments were carried out with Artemia Salina species at various water temperatures. The advantage of this method is the fact that many objects in a large volume can be measured simultaneously.

  13. Ribose Accelerates Gut Motility and Suppresses Mouse Body Weight Gaining

    PubMed Central

    Liu, Yan; Li, Tong-Ruei R; Xu, Cong; Xu, Tian

    2016-01-01

    The increasing prevalence of obesity is closely related to excessive energy consumption. Clinical intervention of energy intake is an attractive strategy to fight obesity. However, the current FDA-approved weight-loss drugs all have significant side effects. Here we show that ribose upregulates gut motility and suppresses mice body weight gain. Ribokinase, which is encoded by Rbks gene, is the first enzyme for ribose metabolism in vivo. Rbks mutation resulted in ribose accumulation in the small intestine, which accelerated gut movement. Ribose oral treatment in wild type mice also enhanced bowel motility and rendered mice resistance to high fat diets. The suppressed weight gain was resulted from enhanced ingested food excretion. In addition, the effective dose of ribose didn't cause any known side effects (i.e. diarrhea and hypoglycemia). Overall, our results show that ribose can regulate gut motility and energy homeostasis in mice, and suggest that administration of ribose and its analogs could regulate gastrointestinal motility, providing a novel therapeutic approach for gastrointestinal dysfunction and weight control. PMID:27194947

  14. Is sperm motility maturation affected by static magnetic fields?

    PubMed Central

    Tablado, L; Pérez-Sánchez, F; Soler, C

    1996-01-01

    Kinematic parameters were evaluated in mouse epididymal extracts to monitor maturation of sperm movement in animals exposed to static magnetic fields using the Sperm-Class Analyzer computerized image analysis system. For this purpose, animals were exposed to a field of 0.7 T generated by a permanent magnet over 10 or 35 days for either 1 or 24 hr/day. The values of the motion endpoints were similar in animals used as controls and in those exposed to the nonionizing radiation, whatever the period of exposure or daily dosage. Changes in motility were observed in all groups: the percentage of total motile and progressive motile spermatozoa increased during passage through the epididymis, with major changes between the caput and corpus epididymides, and the pattern of swimming changed clearly towards more rapid and straighter trajectories. The processes of initiation of sperm motility and maturation of displacement patterns were not then affected by magnetic treatment. Moreover, it appears that sperm production is unaffected because no changes were observed in testicular or epididymal weights after exposure to static magnetic fields. Images Figure 1. Figure 2. Figure 3. PMID:8959411

  15. Motility enhancement of bacteria actuated microstructures using selective bacteria adhesion.

    PubMed

    Park, Sung Jun; Bae, Hyeoni; Kim, Joonhwuy; Lim, Byungjik; Park, Jongoh; Park, Sukho

    2010-07-07

    Microrobots developed by the technological advances are useful for application in various fields. Nevertheless, they have limitations with respect to their actuator and motility. Our experiments aim to determine whether a bioactuator using the flagellated bacteria Serratia marcescens would enhance the motility of microrobots. In this study, we investigate that the flagellated bacteria Serratia marcescens could be utilized as actuators for SU-8 microstructures by bovine serum albumin-selective patterning. Firstly, we analyze the adherence of the bacteria to the SU-8 micro cube by selective patterning using 5% BSA. The results show that number of attached-bacteria in the uncoated side of the selectively- coated micro cube with BSA increased by 200% compared with that in all sides of the non treated micro cube. Secondly, the selectively BSA coated micro cube had 210% higher motility than the uncoated micro cube. The results revealed that the bacteria patterned to a specific site using 5% BSA significantly increase the motility of the bacteria actuated microstructure.

  16. HES6 enhances the motility of alveolar rhabdomyosarcoma cells

    SciTech Connect

    Wickramasinghe, Caroline M; Domaschenz, Renae; Amagase, Yoko; Williamson, Daniel; Missiaglia, Edoardo; Shipley, Janet; Murai, Kasumi; Jones, Philip H

    2013-01-01

    Absract: HES6, a member of the hairy-enhancer-of-split family of transcription factors, plays multiple roles in myogenesis. It is a direct target of the myogenic transcription factor MyoD and has been shown to regulate the formation of the myotome in development, myoblast cell cycle exit and the organization of the actin cytoskeleton during terminal differentiation. Here we investigate the expression and function of HES6 in rhabdomyosarcoma, a soft tissue tumor which expresses myogenic genes but fails to differentiate into muscle. We show that HES6 is expressed at high levels in the subset of alveolar rhabdomyosarcomas expressing PAX/FOXO1 fusion genes (ARMSp). Knockdown of HES6 mRNA in the ARMSp cell line RH30 reduces proliferation and cell motility. This phenotype is rescued by expression of mouse Hes6 which is insensitive to HES6 siRNA. Furthermore, expression microarray analysis indicates that the HES6 knockdown is associated with a decrease in the levels of Transgelin, (TAGLN), a regulator of the actin cytoskeleton. Knockdown of TAGLN decreases cell motility, whilst TAGLN overexpression rescues the motility defect resulting from HES6 knockdown. These findings indicate HES6 contributes to the pathogenesis of ARMSp by enhancing both proliferation and cell motility.

  17. Earthquake-like dynamics in Myxococcus xanthus social motility.

    PubMed

    Gibiansky, Maxsim L; Hu, Wei; Dahmen, Karin A; Shi, Wenyuan; Wong, Gerard C L

    2013-02-05

    Myxococcus xanthus is a bacterium capable of complex social organization. Its characteristic social ("S")-motility mechanism is mediated by type IV pili (TFP), linear actuator appendages that propel the bacterium along a surface. TFP are known to bind to secreted exopolysaccharides (EPS), but it is unclear how M. xanthus manages to use the TFP-EPS technology common to many bacteria to achieve its unique coordinated multicellular movements. We examine M. xanthus S-motility, using high-resolution particle-tracking algorithms, and observe aperiodic stick-slip movements. We show that they are not due to chemotaxis, but are instead consistent with a constant TFP-generated force interacting with EPS, which functions both as a glue and as a lubricant. These movements are quantitatively homologous to the dynamics of earthquakes and other crackling noise systems. These systems exhibit critical behavior, which is characterized by a statistical hierarchy of discrete "avalanche" motions described by a power law distribution. The measured critical exponents from M. xanthus are consistent with mean field theoretical models and with other crackling noise systems, and the measured Lyapunov exponent suggests the existence of highly branched EPS. Such molecular architectures, which are common for efficient lubricants but rare in bacterial EPS, may be necessary for S-motility: We show that the TFP of leading "locomotive" cells initiate the collective motion of follower cells, indicating that lubricating EPS may alleviate the force generation requirements on the lead cell and thus make S-motility possible.

  18. Effects of Ergot Alkaloids on Bovine Sperm Motility In Vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ergot alkaloids are synthesized by endophyte-infected (Neotyphodium coenophialum) tall fescue (Lolium arundinaceum (Schreb.) S.J. Darbyshire). Our objective was to determine direct effects of ergot alkaloids (ergotamine, dihydroergotamine and ergonovine) on the motility of bovine spermatozoa in vit...

  19. Linear scleroderma associated with ptosis and motility disorders.

    PubMed Central

    Suttorp-Schulten, M S; Koornneef, L

    1990-01-01

    A case is reported in which an 11-year-old girl developed progressive ptosis and a subsequent motility disorder of the right eye. The diagnosis linear scleroderma en coup de sabre was established. Atrophy of the upper levator palpebral and superior rectus muscle could be shown on CT scan. Images PMID:2223709

  20. Social motility in African trypanosomes: fact or model?

    PubMed

    Bastin, Philippe; Rotureau, Brice

    2015-02-01

    African trypanosomes grown on agarose plates exhibit behaviours akin to social motility. This phenomenon has not been observed in vivo so far but recently turned out to be instrumental in the definition of two specific stages of the parasite cycle and as a tool to probe for trypanosome sensing functions.

  1. Separation of motile bacteria using drift velocity in a microchannel.

    PubMed

    Ishikawa, Takuji; Shioiri, Tatsuya; Numayama-Tsuruta, Keiko; Ueno, Hironori; Imai, Yohsuke; Yamaguchi, Takami

    2014-03-07

    Separation of certain bacteria from liquids is important in the food, water quality management, bioengineering, and pharmaceutical industries. In this study, we developed a microfluidic device for the hydrodynamic separation of motile bacteria (Escherichia coli) using drift velocity. We first investigated drift tendencies of bacteria and found that cells tended to move in a spanwise direction with similar velocities regardless of the flow rate. When the drift distance was small compared to the wetted perimeter of the cross section, the cells were not separated efficiently. We then investigated the drift phenomenon in more detail using a numerical simulation. Interestingly, the drift phenomenon was observed even without a wall boundary, indicating that drift was caused mainly by the interaction of moving cells with the background shear flow. Finally, we developed a microfluidic device to separate motile bacteria from tracer particles or less motile cells. By decreasing the channel height, the device could successfully separate motile bacteria from other particles or cells with a separation efficiency of about 40%. Connecting microchannels in a series was also found to be effective, which achieved the separation efficiency of about 60%. The knowledge obtained in this study will facilitate the development of other microfluidics devices for use with bacteria.

  2. Possibilities for an Inclusive Society in Singapore: Becoming Inclusive within

    ERIC Educational Resources Information Center

    Lim, Levan

    2009-01-01

    The envisioning of Singapore as an inclusive society has witnessed the most progressive systemic and policy developments concerning people with disabilities in recent years. The building of "heartware" in society (as in the will, values, and attitudes of its citizens) in order to realize the vision of an inclusive society, however,…

  3. Inclusion in the East: Chinese Students' Attitudes towards Inclusive Education

    ERIC Educational Resources Information Center

    Malinen, Olli-Pekka; Savolainen, Hannu

    2008-01-01

    A sample of 523 Chinese university students was given a questionnaire on their attitudes towards the inclusion of children with disabilities into regular classrooms. Factor analysis, analysis of variance, t-test and correlations were used to assess the respondents' general attitude towards inclusion, the factor structure of the attitudes, the…

  4. Inclusive Education: Identifying Teachers' Perceived Stressors in Inclusive Classrooms

    ERIC Educational Resources Information Center

    Brackenreed, Darlene

    2008-01-01

    This research replicates the study conducted by Forlin (2001) in Churchlands, Western Australia. Forlin's Inclusive Education Teacher Stress and Coping Questionnaire was adapted from the original questionnaire to more accurately reflect the language and practice of inclusion in Ontario (Frost & Brackenreed, 2004). The purpose of this study was…

  5. Enacting Inclusion : A Framework for Interrogating Inclusive Practice

    ERIC Educational Resources Information Center

    Florian, Lani; Spratt, Jennifer

    2013-01-01

    This study reports on the development and use of an analytical framework for interrogating the practice of newly qualified mainstream teachers recently graduated from a one-year Professional Graduate Diploma in Education (PGDE) that was informed by a concept of inclusive pedagogy. Inclusive pedagogy is an approach to teaching and learning that…

  6. Student Teachers' Attitudes and Beliefs about Inclusion and Inclusive Practice

    ERIC Educational Resources Information Center

    Beacham, Nigel; Rouse, Martyn

    2012-01-01

    The beliefs and attitudes of teachers are an important element in the development of inclusive education and its associated practices. Teacher education is seen as crucial in helping to develop positive attitudes and beliefs that are thought to promote inclusion, although attempts to reform teacher education in order to address issues of inclusion…

  7. In situ protein folding and activation in bacterial inclusion bodies.

    PubMed

    Gonzalez-Montalban, Nuria; Natalello, Antonino; García-Fruitós, Elena; Villaverde, Antonio; Doglia, Silvia Maria

    2008-07-01

    Recent observations indicate that bacterial inclusion bodies formed in absence of the main chaperone DnaK result largely enriched in functional, properly folded recombinant proteins. Unfortunately, the molecular basis of this intriguing fact, with obvious biotechnological interest, remains unsolved. We have explored here two non-excluding physiological mechanisms that could account for this observation, namely selective removal of inactive polypeptides from inclusion bodies or in situ functional activation of the embedded proteins. By combining structural and functional analysis, we have not observed any preferential selection of inactive and misfolded protein species by the dissagregating machinery during inclusion body disintegration. Instead, our data strongly support that folding intermediates aggregated as inclusion bodies could complete their natural folding process once deposited in protein clusters, which conduces to significant functional activation. In addition, in situ folding and protein activation in inclusion bodies is negatively regulated by the chaperone DnaK.

  8. Effect of Bacterial Motility on Contaminant Mixing in Porous Media

    NASA Astrophysics Data System (ADS)

    Singh, R.; Olson, M. S.; Bioremediation At Drexel

    2010-12-01

    Groundwater flow is typically characterized by laminar flow and therefore contaminant mixing limited conditions prevail in subsurface environments. The presence of porous media introduces tortuosity to groundwater flow paths, thereby enhancing contaminant mixing. In addition, bacterial motility is reported to induce movement in their surrounding liquid, which may enhance contaminant mixing. Enhancement of chemical diffusion coefficients in bulk fluid due to bacterial random motility and chemotaxis has been already reported in literature. The aim of this study is to investigate the effect of bacterial motility on contaminant mixing in the presence of porous media. A microfluidic device was designed and fabricated using standard photolithography and soft-lithography techniques to simulate a contaminant plume in subsurface porous media due to leakage of an underground storage tank. A non-reactive conservative tracer, Dextran solution labeled with FITC (fluorescein isothiocyanate), was used as surrogate for the contaminant and the motile bacterial strain Escherichia coli HCB33 (wild type) was used for the experiments to enhance contaminant mixing. Images were obtained at various cross-sections along the device and fluorescence intensity profile distributions were analyzed to determine the transverse dispersion of the contaminant. Enhancement in contaminant mixing was assessed by comparing the contaminant transverse dispersion coefficients (Dyi) in porous media in presence of motile bacteria, immobilized bacteria, and with no bacteria. In order to quantify the contaminant dispersion coefficients under the various test conditions, experimental data obtained were fitted to concentration profiles predicted by the contaminant advection-dispersion equation for the given experimental conditions (Figure 1). The transverse dispersion coefficient values obtained in the presence of motile bacteria (Dymb)and with no bacteria (Dynb) were 2.49 x 10-4 cm2/s and 1.39 x 10-4 cm2/s

  9. Elucidation of the Photorhabdus temperata Genome and Generation of a Transposon Mutant Library To Identify Motility Mutants Altered in Pathogenesis

    PubMed Central

    Hurst, Sheldon; Rowedder, Holli; Michaels, Brandye; Bullock, Hannah; Jackobeck, Ryan; Abebe-Akele, Feseha; Durakovic, Umjia; Gately, Jon; Janicki, Erik

    2015-01-01

    ABSTRACT The entomopathogenic nematode Heterorhabditis bacteriophora forms a specific mutualistic association with its bacterial partner Photorhabdus temperata. The microbial symbiont is required for nematode growth and development, and symbiont recognition is strain specific. The aim of this study was to sequence the genome of P. temperata and identify genes that plays a role in the pathogenesis of the Photorhabdus-Heterorhabditis symbiosis. A draft genome sequence of P. temperata strain NC19 was generated. The 5.2-Mb genome was organized into 17 scaffolds and contained 4,808 coding sequences (CDS). A genetic approach was also pursued to identify mutants with altered motility. A bank of 10,000 P. temperata transposon mutants was generated and screened for altered motility patterns. Five classes of motility mutants were identified: (i) nonmotile mutants, (ii) mutants with defective or aberrant swimming motility, (iii) mutant swimmers that do not require NaCl or KCl, (iv) hyperswimmer mutants that swim at an accelerated rate, and (v) hyperswarmer mutants that are able to swarm on the surface of 1.25% agar. The transposon insertion sites for these mutants were identified and used to investigate other physiological properties, including insect pathogenesis. The motility-defective mutant P13-7 had an insertion in the RNase II gene and showed reduced virulence and production of extracellular factors. Genetic complementation of this mutant restored wild-type activity. These results demonstrate a role for RNA turnover in insect pathogenesis and other physiological functions. IMPORTANCE The relationship between Photorhabdus and entomopathogenic nematode Heterorhabditis represents a well-known mutualistic system that has potential as a biological control agent. The elucidation of the genome of the bacterial partner and role that RNase II plays in its life cycle has provided a greater understanding of Photorhabdus as both an insect pathogen and a nematode symbiont. PMID

  10. Aquareovirus NS80 recruits viral proteins to its inclusions, and its C-terminal domain is the primary driving force for viral inclusion formation.

    PubMed

    Shao, Ling; Guo, Hong; Yan, Li-Ming; Liu, Huan; Fang, Qin

    2013-01-01

    Cytoplasmic inclusion bodies formed in reovirus-infected cells are the sites of viral replication and assembly. Previous studies have suggested that the NS80 protein of aquareovirus may be involved in the formation of viral inclusion bodies. However, it remains unknown whether other viral proteins are involved in the process, and what regions of NS80 may act coordinately in mediating inclusion formation. Here, we observed that globular cytoplasmic inclusions were formed in virus-infected cells and viral proteins NS80 and NS38 colocalized in the inclusions. During transfection, singly expressed NS80 could form cytoplasmic inclusions and recruit NS38 and GFP-tagged VP4 to these structures. Further treatment of cells with nocodazole, a microtubule inhibitor, did not disrupt the inclusion, suggesting that inclusion formation does not rely on microtubule network. Besides, we identified that the region 530-742 of NS80 was likely the minimal region required for inclusion formation, and the C-tail, coiled-coil region as well as the conserved linker region were essential for inclusion phenotype. Moreover, with series deletions from the N-terminus, a stepwise conversion occurred from large condensed cytoplasmic to small nuclear inclusions, then to a diffused intracellular distribution. Notablely, we found that the nuclear inclusions, formed by NS80 truncations (471 to 513-742), colocalized with cellular protein β-catenin. These data indicated that NS80 could be a major mediator in recruiting NS38 and VP4 into inclusion structures, and the C-terminus of NS80 is responsible for inclusion formation.

  11. Spirochete flagella hook protein self-catalyze a lysinoalanine covalent cross-link for motility

    PubMed Central

    Miller, Michael R.; Miller, Kelly A.; Bian, Jiang; James, Milinda E.; Zhang, Sheng; Lynch, Michael; Callery, Patrick S.; Hettick, Justin M.; Cockburn, Andrew; Liu, Jun; Li, Chunhao; Crane, Brian R.; Charon, Nyles W.

    2016-01-01

    Spirochetes are bacteria responsible for several serious diseases that include Lyme disease (Borrelia burgdorferi), syphilis (Treponema pallidum), leptospirosis (Leptospira interrogans), and contribute to periodontal diseases (Treponema denticola)1. These spirochetes employ an unusual form of flagella-based motility necessary for pathogenicity; indeed, spirochete flagella (periplasmic flagella, PFs) reside and rotate within the periplasmic space2–11. The universal joint or hook that links the rotary motor to the filament is composed of approximately 120–130 FlgE proteins, which in spirochetes form an unusually stable, high-molecular weight complex (HMWC)9,12–17. In other bacteria, the hook can be readily dissociated by treatments such as heat18. In contrast, spirochete hooks are resistant to these treatments, and several lines of evidence indicate that the HMWC is the consequence of covalent cross-linking12,13,17. Here we show that T. denticola FlgE self-catalyzes an interpeptide cross-linking reaction between conserved lysine and cysteine resulting in the formation of an unusual lysinoalanine adduct that polymerizes the hook subunits. Lysinoalanine cross-links are not needed for flagellar assembly, but they are required for cell motility, and hence infection. The self-catalytic nature of FlgE cross-linking has important implications for protein engineering, and its sensitivity to chemical inhibitors provides a new avenue for the development of antimicrobials targeting spirochetes. PMID:27670115

  12. Live tissue viability and chemosensitivity assays using digital holographic motility contrast imaging.

    PubMed

    An, Ran; Turek, John; Matei, Daniela Elena; Nolte, David

    2013-01-01

    Holographic optical coherence imaging is an en face form of optical coherence tomography that uses low-coherence digital holography as a coherence gate to select light from a chosen depth inside scattering tissue. By acquiring successive holograms at a high camera frame rate at a fixed depth, dynamic speckle provides information concerning dynamic light scattering from intracellular motility. Motility contrast imaging (MCI) uses living motion as a label-free and functional biomarker. MCI provides a new form of viability assay and also is applicable for proliferation and cytotoxicity assays. The results presented here demonstrate that low-coherence digital holography can extract viability information from biologically relevant three-dimensional (3D) tissue based on multicellular tumor spheroids by moving beyond the format of two-dimensional cell culture used for conventional high-content analysis. This paper also demonstrates the use of MCI for chemosensitivity assays on tumor exgrafts of excised ovarian cancer tumors responding to standard-of-care cisplatin chemotherapy. This ex vivo application extends the applicability of MCI beyond 3D tissue culture grown in vitro.

  13. Spirochaete flagella hook proteins self-catalyse a lysinoalanine covalent crosslink for motility.

    PubMed

    Miller, Michael R; Miller, Kelly A; Bian, Jiang; James, Milinda E; Zhang, Sheng; Lynch, Michael J; Callery, Patrick S; Hettick, Justin M; Cockburn, Andrew; Liu, Jun; Li, Chunhao; Crane, Brian R; Charon, Nyles W

    2016-08-08

    Spirochaetes are bacteria responsible for several serious diseases, including Lyme disease (Borrelia burgdorferi), syphilis (Treponema pallidum) and leptospirosis (Leptospira interrogans), and contribute to periodontal diseases (Treponema denticola)(1). These spirochaetes employ an unusual form of flagella-based motility necessary for pathogenicity; indeed, spirochaete flagella (periplasmic flagella) reside and rotate within the periplasmic space(2-11). The universal joint or hook that links the rotary motor to the filament is composed of ∼120-130 FlgE proteins, which in spirochaetes form an unusually stable, high-molecular-weight complex(9,12-17). In other bacteria, the hook can be readily dissociated by treatments such as heat(18). In contrast, spirochaete hooks are resistant to these treatments, and several lines of evidence indicate that the high-molecular-weight complex is the consequence of covalent crosslinking(12,13,17). Here, we show that T. denticola FlgE self-catalyses an interpeptide crosslinking reaction between conserved lysine and cysteine, resulting in the formation of an unusual lysinoalanine adduct that polymerizes the hook subunits. Lysinoalanine crosslinks are not needed for flagellar assembly, but they are required for cell motility and hence infection. The self-catalytic nature of FlgE crosslinking has important implications for protein engineering, and its sensitivity to chemical inhibitors provides a new avenue for the development of antimicrobials targeting spirochaetes.

  14. Can balneotherapy improve the bowel motility in chronically constipated middle-aged and elderly patients?

    NASA Astrophysics Data System (ADS)

    Dandinoglu, Taner; Dandin, Ozgur; Ergin, Tuncer; Tihan, Deniz; Akpak, Yasam Kemal; Aydın, Oguz Ugur; Teomete, Uygar

    2016-12-01

    Balneotherapy or spa therapy is usually known for different application forms of medicinal waters and its effects on the human body. Our purpose is to demonstrate the effect of balneotherapy on gastrointestinal motility. A total of 35 patients who were treated for osteoarthritis with balneotherapy from November 2013 through March 2015 at our hospital had a consultation at the general surgery for constipation and defecation disorders. Patients followed by constipation scores, short-form health survey (SF-12), and a colonic transit time (CTT) study before and after balneotherapy were included in this study, and the data of the patients were analyzed retrospectively. The constipation score, SF-12 score, and CTT were found statistically significant after balneotherapy (p < 0.05). The results of our study confirm the clinical finding that a 15-day course of balneotherapy with mineral water from a thermal spring (Bursa, Turkey) improves gastrointestinal motility and reduces laxative consumption in the management of constipation in middle-aged and elderly patients, and it is our belief that treatment with thermal mineral water could considerably improve the quality of life of these patients.

  15. IQGAP3 Is Essential for Cell Proliferation and Motility During Zebrafish Embryonic Development

    PubMed Central

    Fang, Xiaolan; Zhang, Bianhong; Thisse, Bernard; Bloom, George S.; Thisse, Christine

    2015-01-01

    IQGAPs are scaffolding proteins that regulate actin assembly, exocyst function, cell motility, morphogenesis, adhesion and division. Vertebrates express 3 family members: IQGAP1, IQGAP2 and IQGAP3. IQGAP1 is known to stimulate nucleation of branched actin filaments through N-WASP and the Arp2/3 complex following direct binding to cytoplasmic tails of ligand-activated growth factor receptors, including EGFR, VEGFR2 and FGFR1. By contrast, little is known about functions of IQGAP2 or IQGAP3. Using in situ hybridization on whole mount zebrafish (Danio rerio) embryos, we show that IQGAP1 and IQGAP2 are associated with discrete tissues and organs, while IQGAP3 is mainly expressed in proliferative cells throughout embryonic and larval development. Morpholino knockdowns of IQGAP1 and IQGAP2 have little effect on embryo morphology while loss of function of IQGAP3 affects both cell proliferation and cell motility. IQGAP3 morphant phenotypes are similar to those resulting from overexpression of dominant negative forms of Ras or of Fibroblast Growth Factor Receptor 1 (FGFR1), suggesting that IQGAP3 plays a role in FGFR1-Ras-ERK signaling. In support of this hypothesis, dominant negative forms of FGFR1 or Ras could be rescued by co-injection of zebrafish IQGAP3 mRNA, strongly suggesting that IQGAP3 acts as a downstream regulator of the FGFR1-Ras signaling pathway. PMID:26286209

  16. Quorum sensing in Yersinia enterocolitica controls swimming and swarming motility.

    PubMed

    Atkinson, Steve; Chang, Chien-Yi; Sockett, R Elizabeth; Cámara, Miguel; Williams, Paul

    2006-02-01

    The Yersinia enterocolitica LuxI homologue YenI directs the synthesis of N-3-(oxohexanoyl)homoserine lactone (3-oxo-C6-HSL) and N-hexanoylhomoserine lactone (C6-HSL). In a Y. enterocolitica yenI mutant, swimming motility is temporally delayed while swarming motility is abolished. Since both swimming and swarming are flagellum dependent, we purified the flagellin protein from the parent and yenI mutant. Electrophoresis revealed that in contrast to the parent strain, the yenI mutant grown for 17 h at 26 degrees C lacked the 45-kDa flagellin protein FleB. Reverse transcription-PCR indicated that while mutation of yenI had no effect on yenR, flhDC (the motility master regulator) or fliA (the flagellar sigma factor) expression, fleB (the flagellin structural gene) was down-regulated. Since 3-oxo-C6-HSL and C6-HSL did not restore swimming or swarming in the yenI mutant, we reexamined the N-acylhomoserine lactone (AHL) profile of Y. enterocolitica. Using AHL biosensors and mass spectrometry, we identified three additional AHLs synthesized via YenI: N-(3-oxodecanoyl)homoserine lactone, N-(3-oxododecanoyl)homoserine lactone (3-oxo-C12-HSL), and N-(3-oxotetradecanoyl)homoserine lactone. However, none of the long-chain AHLs either alone or in combination with the short-chain AHLs restored swarming or swimming in the yenI mutant. By investigating the transport of radiolabeled 3-oxo-C12-HSL and by introducing an AHL biosensor into the yenI mutant we demonstrate that the inability of exogenous AHLs to restore motility to the yenI mutant is not related to a lack of AHL uptake. However, both AHL synthesis and motility were restored by complementation of the yenI mutant with a plasmid-borne copy of yenI.

  17. Roles of ion transport in control of cell motility.

    PubMed

    Stock, Christian; Ludwig, Florian T; Hanley, Peter J; Schwab, Albrecht

    2013-01-01

    Cell motility is an essential feature of life. It is essential for reproduction, propagation, embryonic development, and healing processes such as wound closure and a successful immune defense. If out of control, cell motility can become life-threatening as, for example, in metastasis or autoimmune diseases. Regardless of whether ciliary/flagellar or amoeboid movement, controlled motility always requires a concerted action of ion channels and transporters, cytoskeletal elements, and signaling cascades. Ion transport across the plasma membrane contributes to cell motility by affecting the membrane potential and voltage-sensitive ion channels, by inducing local volume changes with the help of aquaporins and by modulating cytosolic Ca(2+) and H(+) concentrations. Voltage-sensitive ion channels serve as voltage detectors in electric fields thus enabling galvanotaxis; local swelling facilitates the outgrowth of protrusions at the leading edge while local shrinkage accompanies the retraction of the cell rear; the cytosolic Ca(2+) concentration exerts its main effect on cytoskeletal dynamics via motor proteins such as myosin or dynein; and both, the intracellular and the extracellular H(+) concentration modulate cell migration and adhesion by tuning the activity of enzymes and signaling molecules in the cytosol as well as the activation state of adhesion molecules at the cell surface. In addition to the actual process of ion transport, both, channels and transporters contribute to cell migration by being part of focal adhesion complexes and/or physically interacting with components of the cytoskeleton. The present article provides an overview of how the numerous ion-transport mechanisms contribute to the various modes of cell motility.

  18. Exopolysaccharide biosynthesis genes required for social motility in Myxococcus xanthus.

    PubMed

    Lu, Ann; Cho, Kyunyung; Black, Wesley P; Duan, Xue-Yan; Lux, Renate; Yang, Zhaomin; Kaplan, Heidi B; Zusman, David R; Shi, Wenyuan

    2005-01-01

    Social (S)-motility in Myxococcus xanthus is a flagellum-independent gliding motility system that allows bacteria to move in groups on solid surfaces. S-motility has been shown to require type IV pili (TFP), exopolysaccharide (EPS; a component of fibrils) and lipopolysaccharide (LPS). Previously, information concerning EPS biogenesis in M. xanthus was lacking. In this study, we screened 5000 randomly mutagenized colonies for defects in S-motility and EPS and identified two genetic regions essential for EPS biogenesis: the EPS synthesis (eps) region and the EPS-associated (eas) region. Mutants with insertions in the eps and eas regions were defective in S-motility and fruiting body formation. These mutants failed to bind the dye calcofluor white, indicating that they lacked EPS; however, they retained normal TFP and LPS. Analysis of the eps locus showed several open reading frames (ORFs) that encode homologues to glycosyltransferases, glucanases and EPS transporters as well as regulatory proteins; the eas locus contains two ORFs: one exhibits homology to hypothetical proteins with a conserved domain of unknown function and the other displays no apparent homology to other proteins in the database. Further genetic mutagenesis analysis indicates that the whole eps region is involved in the biosynthesis of fibrils and fibril EPS. The operon at the proximal end of the eps region was analysed by generating in-frame deletion mutations. These mutants showed varying degrees of defects in the bacterium's ability to produce EPS or perform EPS-related functions, confirming the involvement of these genes in M. xanthus EPS biogenesis.

  19. Fluid Inclusions in Extraterrestrial Samples Fact or Fiction?

    NASA Technical Reports Server (NTRS)

    Bodnar, R. J.; Zolensky, M. E.; Gibson, E. K.

    2000-01-01

    Over the years there have been numerous reports of liquid inclusions in meteorites. Roedder reviews the reported occurrences of liquid inclusions in meteorites and states that "silicate-melt inclusions are expectable and apparently ubiquitous, but the presence of actual liquid inclusions (i.e., with moving bubbles at room temperature) would seem almost impossible." The reason for this conclusion is that meteorites (presumably) form in space at high temperatures and very low pressures where liquid water (or carbon dioxide) is not stable. Perhaps the most infamous report of fluid inclusions in meteorites was that of Warner et al. In that study, the authors reported the presence of two-phase, liquid-vapor inclusions in a diogenite from Antarctica. This report of fluid inclusions generated considerable interest in the meteorite community, and caused many to question existing models for the origin of the diogenites. This interest was short-lived however, as later investigations of the same samples showed that the inclusions were most likely artifacts. Rudnick et al. showed that many of the inclusions in meteorites prepared at the Johnson Space Center contained a fluid that fluoresced strongly under the laser beam on the Raman microprobe. They interpreted this to indicate that the inclusions contained Almag oil used in the preparation of thin sections. Presumably, the Almag oil entered empty vesicles along fractures that were opened intermittently during cutting. Here, the occurrence of unambiguous fluid inclusions that could not have been introduced during sample preparation are described in samples from two different extraterrestrial environments. One environment is represented by the SNC (martian) meteorites ALH 84001 and Nakhla. The second environment is represented by the Monahans 1998 meteorite that fell recently in the USA.

  20. Effect of the surface composition of motile Escherichia coli and motile Salmonella species on the direction of galvanotaxis.

    PubMed Central

    Shi, W; Stocker, B A; Adler, J

    1996-01-01

    We have reported that motile Escherichia coli K-12 placed in an electric field swims toward the anode but that motile Salmonella typhimurium strains swim toward the cathode, a phenomenon called galvanotaxis (J. Adler and W. Shi, Cold Spring Harbor Symp. Quant. Biol. 53:23-25, 1988). In the present study, we isolated mutants with an altered direction of galvanotaxis. By further analyses of these mutants and by examination of E. coli and Salmonella strains with altered cell surface structure, we have now established a correlation between the direction of galvanotaxis and the surface structure of the cell: motile rough bacteria (that is, those without O polysaccharide; for example, E. coli K-12 and S. typhimurium mutants of classes galE and rfa) swam toward the anode, whereas motile smooth bacteria (that is, those with O polysaccharide; for example, wild-type S. typhimurium LT2) swam toward the cathode. However, smooth bacteria with acidic polysaccharide capsules (K1 in E. coli and Vi in Salmonella typhi) swam toward the anode. Measurements of passive electrophoretic mobility of strains representative of each set were made. We propose that the different directions of galvanotaxis of rough (or capsulate) bacteria and of smooth bacteria are explicable if the negative electrophoretic mobility of flagellar filaments is less than that of rough bodies but greater than that of smooth bodies. PMID:8576046

  1. Ceramide limits phosphatidylinositol-3-kinase C2β-controlled cell motility in ovarian cancer: potential of ceramide as a metastasis-suppressor lipid

    PubMed Central

    Kitatani, Kazuyuki; Toshinori, Usui; Sriraman, Shravan Kumar; Toyoshima, Masafumi; Ishibashi, Masumi; Shigeta, Shogo; Nagase, Satoru; Sakamoto, Masahiro; Ogiso, Hideo; Okazaki, Toshiro; Hannun, Yusuf A.; Torchilin, Vladimir P.; Yaegashi, Nobuo

    2015-01-01

    Targeting cell motility, which is required for dissemination and metastasis, has therapeutic potential for ovarian cancer metastasis, and regulatory mechanisms of cell motility need to be uncovered for developing novel therapeutics. Invasive ovarian cancer cells spontaneously formed protrusions, such as lamellipodia, which are required for generating locomotive force in cell motility. siRNA screening identified class II phosphatidylinositol 3-kinase C2β (PI3KC2β) as the predominant isoform of PI3K involved in lamellipodia formation of ovarian cancer cells. The bioactive sphingolipid ceramide has emerged as an antitumorigenic lipid, and treatment with short-chain C6-ceramide decreased the number of ovarian cancer cells with PI3KC2β-driven lamellipodia. Pharmacological analysis demonstrated that long-chain ceramide regenerated from C6-ceramide through the salvage/recycling pathway, at least in part, mediated the action of C6-ceramide. Mechanistically, ceramide was revealed to interact with the PIK-catalytic domain of PI3KC2β and affect its compartmentalization, thereby suppressing PI3KC2β activation and its driven cell motility. Ceramide treatment also suppressed cell motility promoted by epithelial growth factor, which is a prometastatic factor. To examine the role of ceramide in ovarian cancer metastasis, ceramide liposomes were employed and confirmed to suppress cell motility in vitro. Ceramide liposomes had an inhibitory effect on peritoneal metastasis in a murine xenograft model of human ovarian cancer. Metastasis of PI3KC2β knocked-down cells was insensitive to treatment with ceramide liposomes, suggesting specific involvement of ceramide interaction with PI3KC2β in metastasis suppression. Our study identified ceramide as a bioactive lipid that limits PI3KC2β-governed cell motility, and ceramide is proposed to serve as a metastasis-suppressor lipid in ovarian cancer. These findings could be translated into developing ceramide-based therapy for

  2. Inhibitory Effects of Macrotetrolides from Streptomyces spp. On Zoosporogenesis and Motility of Peronosporomycete Zoospores Are Likely Linked with Enhanced ATPase Activity in Mitochondria

    PubMed Central

    Islam, Md. Tofazzal; Laatsch, Hartmut; von Tiedemann, Andreas

    2016-01-01

    The release of zoospores from sporangia and motility of the released zoospores are critical in the disease cycle of the Peronosporomycetes that cause devastating diseases in plants, fishes, animals and humans. Disruption of any of these asexual life stages eliminates the possibility of pathogenesis. In the course of screening novel bioactive secondary metabolites, we found that extracts of some strains of marine Streptomyces spp. rapidly impaired motility and caused subsequent lysis of zoospores of the grapevine downy mildew pathogen Plasmopara viticola at 10 μg/ml. We tested a number of secondary metabolites previously isolated from these strains and found that macrotetrolide antibiotics such as nonactin, monactin, dinactin and trinactin, and nactic acids such as (+)-nonactic acid, (+)-homonactic acid, nonactic acid methyl ester, homonactic acid methyl ester, bonactin and feigrisolide C impaired motility and caused subsequent lysis of P. viticola zoospores in a dose- and time-dependent manners with dinactin being the most active compound (MIC 0.3 μg/ml). A cation channel-forming compound, gramicidin, and a carrier of monovalent cations, nigericin also showed similar biological activities. Among all 12 compounds tested, gramicidin most potently arrested the motility of zoospores at concentrations starting from 0.1 μg/ml. All macrotetrolide antibiotics also displayed similar motility impairing activities against P. viticola, Phytophthora capsici, and Aphanomyces cochlioides zoospores indicating non-specific biological effects of these compounds toward peronosporomyctes. Furthermore, macrotetrolide antibiotics and gramicidin also markedly suppressed the release of zoospores from sporangia of P. viticola in a dose-dependent manner. As macrotetrolide antibiotics and gramicidin are known as enhancers of mitochondrial ATPase activity, inhibition of zoosporogenesis and motility of zoospores by these compounds are likely linked with hydrolysis of ATP through enhanced

  3. Early Childhood Inclusion in Turkey

    ERIC Educational Resources Information Center

    Diken, Ibrahim H.; Rakap, Salih; Diken, Ozlem; Tomris, Gozde; Celik, Secil

    2016-01-01

    Inclusion of young children with disabilities into regular preschool classrooms is a common practice that has been implemented for several decades in industrialized nations around the world, and many developing countries including Turkey have been developing and implementing laws, regulation, and services to support inclusion and teaching in…

  4. Stiffening solids with liquid inclusions

    NASA Astrophysics Data System (ADS)

    Style, Robert W.; Boltyanskiy, Rostislav; Allen, Benjamin; Jensen, Katharine E.; Foote, Henry P.; Wettlaufer, John S.; Dufresne, Eric R.

    2015-01-01

    From bone and wood to concrete and carbon fibre, composites are ubiquitous natural and synthetic materials. Eshelby’s inclusion theory describes how macroscopic stress fields couple to isolated microscopic inclusions, allowing prediction of a composite’s bulk mechanical properties from a knowledge of its microstructure. It has been extended to describe a wide variety of phenomena from solid fracture to cell adhesion. Here, we show experimentally and theoretically that Eshelby’s theory breaks down for small liquid inclusions in a soft solid. In this limit, an isolated droplet’s deformation is strongly size-dependent, with the smallest droplets mimicking the behaviour of solid inclusions. Furthermore, in opposition to the predictions of conventional composite theory, we find that finite concentrations of small liquid inclusions enhance the stiffness of soft solids. A straightforward extension of Eshelby’s theory, accounting for the surface tension of the solid-liquid interface, explains our experimental observations. The counterintuitive stiffening of solids by fluid inclusions is expected whenever inclusion radii are smaller than an elastocapillary length, given by the ratio of the surface tension to Young’s modulus of the solid matrix. These results suggest that surface tension can be a simple and effective mechanism to cloak the far-field elastic signature of inclusions.

  5. Promoting Inclusive Education in Ghana

    ERIC Educational Resources Information Center

    Djietror, Beauty B. K.; Okai, Edward; Kwapong, Olivia A. T. Frimpong

    2011-01-01

    Inclusive education is critical for nation building. The government of Ghana has put in measures for promoting inclusion from basic through to tertiary level of education. Some of these measures include expansion of school facilities, implementation of the Free Compulsory Universal Basic Education (FCUBE); the change of policy on girls who drop…

  6. Inclusion in Malaysian Integrated Preschools

    ERIC Educational Resources Information Center

    Sukumaran, Sailajah; Loveridge, Judith; Green, Vanessa A.

    2015-01-01

    Inclusive education has been introduced through a number of policy developments in Malaysia over the last 10 years but there is little research investigating the extent and nature of inclusive education for preschoolers with special educational needs (SEN). This study surveyed both regular and special education teachers in Malaysian integrated…

  7. Building Inclusive Cities and Communities

    ERIC Educational Resources Information Center

    Freiler, Christa

    2008-01-01

    Canada prides itself on being an inclusive country. Immigrants from all over the world arrive in Canada's cities with their families because they feel welcome and safe. According to research, engagement towards social inclusion increased among Canadians during the last 30 last years. These changing values resulted in the creation of official…

  8. Early Childhood Inclusion in Spain

    ERIC Educational Resources Information Center

    Giné, Climent; Balcells-Balcells, Anna; Cañadas, Margarita; Paniagua, Gema

    2016-01-01

    This article describes early childhood inclusion in educational settings in Spain. First, we address the legislative framework of preschool education in Spain and offer a brief analysis of some relevant issues, including the current situation of early childhood education and inclusion at this stage. Second, current policies and practices relating…

  9. In Support of Unfinished Inclusion

    ERIC Educational Resources Information Center

    Hausstätter, Rune Sarromaa

    2014-01-01

    This article claims that the radical potential inherent in the origins of inclusive education has been altered into a tool for protecting the status quo. Drawing on ideas from the essay "The Unfinished" by Thomas Mathiesen (1971), I discuss inclusion as a potential alternative to mainstream education and argue that the potential power of…

  10. Creative Educational Practices for Inclusion

    ERIC Educational Resources Information Center

    Piske, Fernanda Hellen Ribeiro; Stoltz, Tania; Machado, Jarci

    2014-01-01

    Inclusion of gifted students depends on several aspects to happen in the school context, and one of the most important aspects to include these children at school is creative educational practices. Teaching with art is a good possibility to make children feel motivated to attend school. In the school context, the inclusion of these children could…

  11. Social Inclusion and Metrolingual Practices

    ERIC Educational Resources Information Center

    Otsuji, Emi; Pennycook, Alastair

    2011-01-01

    In this paper, we explore the implications of metrolingual language practices for how we understand social inclusion. A vision of social inclusion that includes bi- and multilingual capacities may comprise an appreciation of a diversity of languages other than English, and the skills and capabilities of multilingual language users, yet it is all…

  12. Friendship in Inclusive Physical Education

    ERIC Educational Resources Information Center

    Seymour, Helena; Reid, Greg; Bloom, Gordon A.

    2009-01-01

    Social interaction and development of friendships between children with and without a disability are often proposed as potential outcomes of inclusive education. Physical activity specialists assert that exercise and sport environments may be conducive to social and friendship outcomes. This study investigated friendship in inclusive physical…

  13. Implications of caveolae in testicular and epididymal myoid cells to sperm motility.

    PubMed

    Oliveira, Regiana L; Parent, Adam; Cyr, Daniel G; Gregory, Mary; Mandato, Craig A; Smith, Charles E; Hermo, Louis

    2016-06-01

    Seminiferous tubules of the testis and epididymal tubules in adult rodents are enveloped by contractile myoid cells, which move sperm and fluids along the male reproductive tract. Myoid cells in the testis influence Sertoli cells by paracrine signaling, but their role in the epididymis is unknown. Electron microscopy revealed that elongated myoid cells formed several concentric layers arranged in a loose configuration. The edges of some myoid cells in a given layer closely approximated one another, and extended small foot-like processes to cells of overlying layers. Gap junction proteins, connexins 32 and 43, were detected within the myoid cell layers by immunohistochemistry. These myoid cells also had caveolae that contained caveolin-1 and cavin-1 (also known as PTRF). The number of caveolae per unit area of plasma membrane was significantly reduced in caveolin-1-deficient mice (Cav1(-/-) ). Morphometric analyses of Cav1-null testes revealed an enlargement in whole-tubule and epithelial profile areas, whereas these parameters were slightly reduced in the epididymis. Although sperm are non-motile as they pass through the proximal epididymis, statistical analyses of cauda epididymidis sperm concentrations revealed no significant differences between wild-type and Cav1(-/-) mice. Motility analyses, however, indicated that sperm velocity parameters were reduced while beat cross frequency was higher in gametes of Cav1(-/-) mice. Thus while caveolae and their associated proteins are not necessary for myoid cell contractility, they appear to be crucial for signaling with the epididymal epithelium to regulate the proper acquisition of sperm motility. Mol. Reprod. Dev. 83: 526-540, 2016. © 2016 Wiley Periodicals, Inc.

  14. Age-Related Differences in Clinical Characteristics and Esophageal Motility in Patients with Dysphagia.

    PubMed

    Nakato, Rui; Manabe, Noriaki; Kamada, Tomoari; Matsumoto, Hideo; Shiotani, Akiko; Hata, Jiro; Haruma, Ken

    2016-12-02

    Dysphagia in elderly patients has a major effect on nutrition and quality of life (QOL). Although several studies have shown that aging itself is associated with changes in esophageal motility, the impact of these changes on dysphagia symptoms and QOL is unknown. This study assessed the manometric diagnoses of elderly patients with dysphagia compared with diagnoses in younger counterparts. Participants included 116 consecutive patients examined for dysphagia from 2007 to 2014. We divided patients into three groups by age: Group A, 66 years and older (24 men, 23 women); Group B, 45-65 years (18 men, 24 women); and Group C, 44 years and younger (15 men, 12 women). The three groups were compared in regard to symptoms, esophageal motility, and health-related QOL (HRQOL). All patients underwent esophageal manometry examination and completed a self-administered questionnaire concerning their symptoms; HRQOL assessment was based on results of the Short Form-8 General Health Survey. Symptoms rated ≥4 points on the Likert scale were defined as significant. Although all patients had dysphagia as a major symptom, more elderly patients reported globus sensation, whereas more young patients reported heartburn as the primary symptom. Manometric diagnoses were generally similar across the three groups. Ineffective esophageal motility was more prevalent in Groups A and C than in Group B, although the difference was not statistically significant. No significant differences in manometric parameters or HRQOL were detected among the three groups. Despite differences in symptom patterns, broad manometric diagnoses and impairment of HRQOL in elderly patients with dysphagia are similar to those in younger counterparts.

  15. Vimentin as a Marker of Early Differentiating, Highly Motile Corneal Epithelial Cells.

    PubMed

    Castro-Muñozledo, Federico; Meza-Aguilar, Diana G; Domínguez-Castillo, Rocío; Hernández-Zequinely, Veremundo; Sánchez-Guzmán, Erika

    2017-04-01

    Vimentin (Vim), a cytoskeletal intermediate filament, is part of a naturally occurring reversible program, the Epithelial-Mesenchymal Transition (EMT), which converts epithelial cells into mesenchymal-like derivatives. Based on previous results showing that epithelial cells co-express Vim and keratin (Krt) as part of a cytoskeletal network which confers them a highly motile phenotype, we explored the role of Vim in rabbit corneal epithelial cells or RCE1(5T5) cells, an established model of corneal epithelial differentiation. Vim and keratin filaments were co-expressed in cells localized at the proliferative/migratory rim of the growing colonies, but not in basal cells from the center of the colonies nor at suprabasal cell layers. Flow cytometry and qPCR demonstrated that there was a decrease in Krt(+) /Vim(+) cell number and ΔNp63α expression when cells reached confluence and formed a 4-5 layered epithelium, while there was a concomitant increase of both Pax-6 expression and Krt(+) /Vim(-) cells. Inhibition of cell proliferation with mitomycin C did not modify cell motility nor the expression of Vim. We studied the distribution and expression of α6 integrin, a protein also involved in cell migration. The results demonstrated that α6 integrin had a distribution which was, in part, co-linear with Vim at the proliferative/migratory rim of cell colonies, suggesting an indirect interaction between these proteins. Immunoprecipitation and immunostaining assays indicated that plectin might be mediating such interaction. These data suggest that Vim expression in corneal epithelium is found in a cell population composed of highly motile cells with a Vim(+) /Krt(+) /ΔNp63α(+) /Pax-6(low) /α6 integrin(+) phenotype. J. Cell. Physiol. 232: 818-830, 2017. © 2016 Wiley Periodicals, Inc.

  16. Motility of Marichromatium gracile in Response to Light, Oxygen, and Sulfide

    PubMed Central

    Thar, Roland; Kühl, Michael

    2001-01-01

    The motility of the purple sulfur bacterium Marichromatium gracile was investigated under different light regimes in a gradient capillary setup with opposing oxygen and sulfide gradients. The gradients were quantified with microsensors, while the behavior of swimming cells was studied by video microscopy in combination with a computerized cell tracking system. M. gracile exhibited photokinesis, photophobic responses, and phobic responses toward oxygen and sulfide. The observed migration patterns could be explained solely by the various phobic responses. In the dark, M. gracile formed an ∼500-μm-thick band at the oxic-anoxic interface, with a sharp border toward the oxic zone always positioned at ∼10 μM O2. Flux calculations yielded a molar conversion ratio Stot/O2 of 2.03:1 (Stot = [H2S] + [HS−] + [S2−]) for the sulfide oxidation within the band, indicating that in darkness the bacteria oxidized sulfide incompletely to sulfur stored in intracellular sulfur globules. In the light, M. gracile spread into the anoxic zone while still avoiding regions with >10 μM O2. The cells also preferred low sulfide concentrations if the oxygen was replaced by nitrogen. A light-dark transition experiment demonstrated a dynamic interaction between the chemical gradients and the cell's metabolism. In darkness and anoxia, M. gracile lost its motility after ca. 1 h. In contrast, at oxygen concentrations of >100 μM with no sulfide present the cells remained viable and motile for ca. 3 days both in light and darkness. Oxygen was respired also in the light, but respiration rates were lower than in the dark. Observed aggregation patterns are interpreted as effective protection strategies against high oxygen concentrations and might represent first stages of biofilm formation. PMID:11722886

  17. Resveratrol Impairs Glioma Stem Cells Proliferation and Motility by Modulating the Wnt Signaling Pathway

    PubMed Central

    Romano, Gabriele; Cadamuro, Massimiliano; Bazzoni, Riccardo; Butta, Valentina; Paoletta, Laura; Dalprà, Leda; Strazzabosco, Mario; Lavitrano, Marialuisa; Giovannoni, Roberto; Bentivegna, Angela

    2017-01-01

    Glioblastoma multiforme (GBM) is a grade IV astrocytoma and the most common form of malignant brain tumor in adults. GBM remains one of the most fatal and least successfully treated solid tumors: current therapies provide a median survival of 12–15 months after diagnosis, due to the high recurrence rate. Glioma Stem Cells (GSCs) are believed to be the real driving force of tumor initiation, progression and relapse. Therefore, better therapeutic strategies GSCs-targeted are needed. Resveratrol is a polyphenolic phytoalexin found in fruits and vegetables displaying pleiotropic health benefits. Many studies have highlighted its chemo-preventive and chemotherapeutic activities in a wide range of solid tumors. In this work, we analyzed the effects of Resveratrol exposure on cell viability, proliferation and motility in seven GSC lines isolated from GBM patients. For the first time in our knowledge, we investigated Resveratrol impact on Wnt signaling pathway in GSCs, evaluating the expression of seven Wnt signaling pathway-related genes and the protein levels of c-Myc and β-catenin. Finally, we analyzed Twist1 and Snail1 protein levels, two pivotal activators of epithelial-mesenchymal transition (EMT) program. Results showed that although response to Resveratrol exposure was highly heterogeneous among GSC lines, generally it was able to inhibit cell proliferation, increase cell mortality, and strongly decrease cell motility, modulating the Wnt signaling pathway and the EMT activators. Treatment with Resveratrol may represent a new interesting therapeutic approach, in order to affect GSCs proliferation and motility, even if further investigations are needed to deeply understand the GSCs heterogeneous response. PMID:28081224

  18. Resveratrol Impairs Glioma Stem Cells Proliferation and Motility by Modulating the Wnt Signaling Pathway.

    PubMed

    Cilibrasi, Chiara; Riva, Gabriele; Romano, Gabriele; Cadamuro, Massimiliano; Bazzoni, Riccardo; Butta, Valentina; Paoletta, Laura; Dalprà, Leda; Strazzabosco, Mario; Lavitrano, Marialuisa; Giovannoni, Roberto; Bentivegna, Angela

    2017-01-01

    Glioblastoma multiforme (GBM) is a grade IV astrocytoma and the most common form of malignant brain tumor in adults. GBM remains one of the most fatal and least successfully treated solid tumors: current therapies provide a median survival of 12-15 months after diagnosis, due to the high recurrence rate. Glioma Stem Cells (GSCs) are believed to be the real driving force of tumor initiation, progression and relapse. Therefore, better therapeutic strategies GSCs-targeted are needed. Resveratrol is a polyphenolic phytoalexin found in fruits and vegetables displaying pleiotropic health benefits. Many studies have highlighted its chemo-preventive and chemotherapeutic activities in a wide range of solid tumors. In this work, we analyzed the effects of Resveratrol exposure on cell viability, proliferation and motility in seven GSC lines isolated from GBM patients. For the first time in our knowledge, we investigated Resveratrol impact on Wnt signaling pathway in GSCs, evaluating the expression of seven Wnt signaling pathway-related genes and the protein levels of c-Myc and β-catenin. Finally, we analyzed Twist1 and Snail1 protein levels, two pivotal activators of epithelial-mesenchymal transition (EMT) program. Results showed that although response to Resveratrol exposure was highly heterogeneous among GSC lines, generally it was able to inhibit cell proliferation, increase cell mortality, and strongly decrease cell motility, modulating the Wnt signaling pathway and the EMT activators. Treatment with Resveratrol may represent a new interesting therapeutic approach, in order to affect GSCs proliferation and motility, even if further investigations are needed to deeply understand the GSCs heterogeneous response.

  19. EFFECT OF CRYOPRESERVATION AND THEOPHYLLINE ON MOTILITY CHARACTERISTICS OF LAKE STURGEON (ACIPENSER FULVESCENS) SPERMATOZOA

    EPA Science Inventory

    Computer-assisted motility analysis (CASA) was used to evaluate the effect of cryopreservation and theophylline treatment on sperm motility of lake sturgeon (Acipenser fulvescens).Motility was recorded at 0 and 5 min postactivation.The effect of cryopreservation on sperm acrosin-...

  20. OBJECTIVE ANALYSIS OF SPERM MOTILITY IN THE LAKE STURGEON, ACIPENSER FULVESCENS: ACTIVATION AND INHIBITION CONDITIONS

    EPA Science Inventory

    An objective analysis of the duration of motility of sperm from the lake sturgeon, Acipenser fulvescens, has been performed using computer-assisted sperm motion analysis at 200 frames/s. Motility was measured in both 1993 and 1994. The percentage of activated motile sperm and the...

  1. Study of bacterial motility using optical tweezers

    NASA Astrophysics Data System (ADS)

    Chattopadhyay, Suddhashil

    Bacteria are arguably the simplest of known microorganisms, forming a fundamental part of the world we live in. Many functions they perform are found in scaled-up versions in higher organisms. Among many advanced functions, bacteria possess the ability to move in search for nutrients and favorable growth conditions. Measurement of the dynamical variables associated with bacterial swimming has proven to be difficult due to the lack of an accurate and convenient tool. In the past optical traps have been used for the manipulation of microscopic objects and measurement of minute forces. Herein, I have devised techniques for use of optical traps for direct measurement of the dynamics of bacterial swimming and chemotaxis, shedding light on the propulsion apparatus and sensory systems. A detailed analysis is performed to explore the effects of non-local hydrodynamic interactions on the swimming of single cells. Due to the lack of reliable measurement techniques, experimentalists often use theoretical models to estimate bacterial dynamics, the validity of which are tested. I emphasize the shortcomings of the very popular Resistive Force Theory (RFT) and indicate how the more rigorous Slender Body Theory (SBT) is able to overcome the limitations. In addition the chemotaxis of the marine bacterial strain Vibrio alginolyticus is studied with the revelation of a previously unknown chemotactic mechanism. Direct observations showed that these cells are able to bend their flagella to impart direction changes, which is paramount for an effective search strategy. This interesting find opens several intriguing questions pertaining to chemotaxis.

  2. Motility and Ultrastructure of Spirochaeta thermophila

    PubMed Central

    Wirth, Reinhard; Ugele, Matthias; Wanner, Gerhard

    2016-01-01

    We analyze here for the first time the swimming behavior of a thermophilic, strictly anaerobic Spirochete, namely Spirochaeta thermophila using high temperature light microscopy. Our data show that S. thermophila very rapidly can change its morphology during swimming, resulting in cells appearing nearly linear, in cells possessing three different spiral forms, and in cells being linear at one end and spiral at the other end. In addition cells can rapidly bend by up to 180°, with their ends coming into close contact. We combine electron with light microscopy to explain these various cell morphologies. Swimming speeds for cells with the various morphologies did not differ significantly: the average speed was 33 (± 8) μm/s, with minimal and maximal speeds of 19 and 59 μm/s, respectively. Addition of gelling agents like polyvinylpyrrolidone or methyl cellulose to the growth medium resulted in lower and not higher swimming speeds, arguing against the idea that the highly unusual cell body plan of S. thermophila enables cells to swim more efficiently in gel-like habitats. PMID:27790206

  3. Effects of physical factors on the swarming motility of text itPseudomonas aeruginosa

    NASA Astrophysics Data System (ADS)

    Si, Tieyan; Ma, Zidong; Tang, Wai Shing; Yang, Alexander; Tang, Jay

    Many species of bacteria can spread over a semi-solid surface via a particular form of collective motion known as surface swarming. Using Pseudomonas aeruginosa as a model organism, we investigate physical factors that either facilitate or restrict the swarming motility. The semi-solid surface is typically formed by 0.5-1% agar containing essential nutrients for the bacterial growth and proliferation. Most bacterial species, including P. aeruginosa, synthesize bio-surfactants to aid in swarming. We found addition of exogenous surfactants such as triton into the agar matrix enhances the swarming. In contrast, increasing agar percentage, infusing osmolites, and adding viscous agents all decrease swarming. We propose that the swarming speed is restricted by the rate of water supply from within the agar gel and by the line tension at the swarm front involving three materials in contact: the air, the bacteria propelled liquid film, and the agar substrate.

  4. Gadolinium, a mechano-sensitive channel blocker, inhibits osmosis-initiated motility of sea- and freshwater fish sperm, but does not affect human or ascidian sperm motility.

    PubMed

    Krasznai, Zoltán; Morisawa, Masaaki; Krasznai, Zoárd Tibor; Morisawa, Sachiko; Inaba, Kazuo; Bazsáné, Zsuzsa Kassai; Rubovszky, Bálint; Bodnár, Béla; Borsos, Antal; Márián, Teréz

    2003-08-01

    Exposure to hypo-osmotic or hyperosmotic environment triggers the initiation of fish sperm motility. In this article, we report that calcium and potassium channel blockers do not influence motility of puffer fish sperm but calmodulin antagonists reversibly decrease it, suggesting that calmodulin-Ca(2+) interactions are prerequisite for the initiation of sperm motility in this species. Gadolinium (a stretch activated ion channel blocker) decreased the motility of puffer fish sperm from 92 +/- 3% to 6 +/- 3% and that of carp sperm from 91 +/- 7% to 3.5 +/- 4.3% in a dose-dependent manner (10-40 micro M). The effect of gadolinium was reversible, suggesting that stretch activated ion channels participate in the initiation of sperm motility of the two species. Gadolinium inhibits changes in the isoelectric point of certain proteins of puffer fish sperm, which occur when sperm motility is initiated in a hypertonic solution. Anisotropy measurements showed that hypo-osmotic treatment, which initiates carp sperm motility, increased membrane fluidity. When hypo-osmotic treatment was given in the presence of gadolinium, the sperm membrane remained as rigid as in quiescent cells, while motility was blocked. By contrast, gadolinium did not influence the motility parameters of Ciona or human sperm. Based on these lines of evidence, we suggest that conformational changes of mechanosensitive membrane proteins are involved in osmolality-dependent but not osmolality-independent sperm.

  5. The alginate regulator AlgR and an associated sensor FimS are required for twitching motility in Pseudomonas aeruginosa.

    PubMed Central

    Whitchurch, C B; Alm, R A; Mattick, J S

    1996-01-01

    Mucoid strains of Pseudomonas aeruginosa isolated from the lungs of cystic fibrosis patients produce large amounts of the exopolysaccharide alginate. AlgR has long been considered a key regulator of alginate production, but its cognate sensor has not been identified. Here we show that AlgR is required for twitching motility, which is a form of bacterial surface translocation mediated by type 4 fimbriae. Adjacent to algR we have identified a sensor gene (fimS), which is also required for twitching motility. However, FimS does not appear to be required for alginate production in mucoid strains. FimS and AlgR are representative of a new subclass of two-component transmitter-receiver regulatory systems. The alternative sigma factor AlgU also affects both alginate production and twitching motility. Therefore, these two virulence determinants appear to be closely associated and coordinately regulated. Images Fig. 1 Fig. 2 Fig. 3 PMID:8790418

  6. Listeria's right-handed helical rocket-tail trajectories: mechanistic implications for force generation in actin-based motility.

    PubMed

    Zeile, William L; Zhang, Fangliang; Dickinson, Richard B; Purich, Daniel L

    2005-02-01

    Listeria monocytogenes forms right-handed helical rocket tail trajectories during actin-based motility in cell-free extracts, and this stereochemical feature is consistent with actoclampin's affinity-modulated, clamped-filament elongation model [Dickinson and Purich, 2002: Biophys J 82:605-617]. In that mechanism, right-handed torque is generated by an end-tracking molecular motor, each comprised of a filament barbed end and clamping protein that processively traces the right-handed helix of its filament partner. By contrast, torque is not a predicted property of those models (e.g., elastic propulsion, elastic Brownian ratchet, tethered ratchet, and insertional polymerization models) requiring filament barbed ends to depart/detach from the motile object's surface during/after each monomer-addition step. Helical trajectories also explain why Listeria undergoes longitudinal-axis rotation on a length-scale matching the helical periodicity of Listeria's rocket tails.

  7. Inclusion of seminal plasma in sperm cryopreservation of Iberian pig.

    PubMed

    Gómez-Fernández, José; Gómez-Izquierdo, Emilio; Tomás, Cristina; González-Bulnes, Antonio; Sánchez-Sánchez, Raúl; de Mercado, Eduardo

    2012-01-01

    The aim of the present study was to evaluate the inclusion of seminal plasma (SP) in the freezing extender, trying to preserve as much as possible of SP with spermatozoa from Iberian pigs, thus improving the conservation of animal genetic resources of this breed. Experiment 1, evaluated the effect of substituting water with SP as diluent in the freezing media in different proportions (0%, 10%, 25%, 50%, 75% and 100%), over pre-freezing (at 10°C and 5°C) and post-thawing sperm quality. The results showed that over 50% of SP in the extender, significantly decreased sperm quality in comparison to the control sample (0% SP) and the samples with 10% and 25% of SP (P<0.05). No significant differences were found between the control sample and the samples with 10% and 25% SP (P>0.05), but treatment with 25% did not show significant differences between the time of incubation at 37°C after thawing (P>0.05), showing greater sperm quality resistance over time. Experiment 2, evaluated the effect of prolonged incubation period, until 480min (simulating the lifespan of sperm in the female genital tract), of sperm samples with 0%, 10% and 25% of SP. Treatment with 25% of SP maintained better sperm quality over time, compared to control sample. Significant differences were observed especially in the parameters of motility analysis (TMS, total motile spermatozoa; PMS: progressive motility spermatozoa. P<0.05). In Experiment 3, the effect of the presence of SP was evaluated during the thawing process. Although some differences were observed between treatments, these differences were not as clear as the previous experiments. In conclusion, replacement of 25% of the water by SP as diluent in the freezing extender could be considered the maximum percentage of inclusion, without harmful effects to the sperm. In addition, this proportion of SP maintained Iberian sperm quality for longer time when it was present during the freezing and thawing process.

  8. Microbial Morphology and Motility as Biosignatures for Outer Planet Missions

    PubMed Central

    Lindensmith, Chris; Deming, Jody W.; Fernandez, Vicente I.; Stocker, Roman

    2016-01-01

    Abstract Meaningful motion is an unambiguous biosignature, but because life in the Solar System is most likely to be microbial, the question is whether such motion may be detected effectively on the micrometer scale. Recent results on microbial motility in various Earth environments have provided insight into the physics and biology that determine whether and how microorganisms as small as bacteria and archaea swim, under which conditions, and at which speeds. These discoveries have not yet been reviewed in an astrobiological context. This paper discusses these findings in the context of Earth analog environments and environments expected to be encountered in the outer Solar System, particularly the jovian and saturnian moons. We also review the imaging technologies capable of recording motility of submicrometer-sized organisms and discuss how an instrument would interface with several types of sample-collection strategies. Key Words: In situ measurement—Biosignatures—Microbiology—Europa—Ice. Astrobiology 16, 755–774. PMID:27552160

  9. A Structural Basis for How Motile Cilia Beat.

    PubMed

    Satir, Peter; Heuser, Thomas; Sale, Winfield S

    2014-12-01

    The motile cilium is a mechanical wonder, a cellular nanomachine that produces a high-speed beat based on a cycle of bends that move along an axoneme made of 9+2 microtubules. The molecular motors, dyneins, power the ciliary beat. The dyneins are compacted into inner and outer dynein arms, whose activity is highly regulated to produce microtubule sliding and axonemal bending. The switch point hypothesis was developed long ago to account for how sliding in the presence of axonemal radial spoke-central pair interactions causes the ciliary beat. Since then, a new genetic, biochemical, and structural complexity has been discovered, in part, with Chlamydomonas mutants, with high-speed, high-resolution analysis of movement and with cryoelectron tomography. We stand poised on the brink of new discoveries relating to the molecular control of motility that extend and refine our understanding of the basic events underlying the switching of arm activity and of bend formation and propagation.

  10. A Structural Basis for How Motile Cilia Beat

    PubMed Central

    Satir, Peter; Heuser, Thomas; Sale, Winfield S.

    2014-01-01

    The motile cilium is a mechanical wonder, a cellular nanomachine that produces a high-speed beat based on a cycle of bends that move along an axoneme made of 9+2 microtubules. The molecular motors, dyneins, power the ciliary beat. The dyneins are compacted into inner and outer dynein arms, whose activity is highly regulated to produce microtubule sliding and axonemal bending. The switch point hypothesis was developed long ago to account for how sliding in the presence of axonemal radial spoke–central pair interactions causes the ciliary beat. Since then, a new genetic, biochemical, and structural complexity has been discovered, in part, with Chlamydomonas mutants, with high-speed, high-resolution analysis of movement and with cryoelectron tomography. We stand poised on the brink of new discoveries relating to the molecular control of motility that extend and refine our understanding of the basic events underlying the switching of arm activity and of bend formation and propagation. PMID:26955066

  11. Microbial Morphology and Motility as Biosignatures for Outer Planet Missions

    NASA Astrophysics Data System (ADS)

    Nadeau, Jay; Lindensmith, Chris; Deming, Jody W.; Fernandez, Vicente I.; Stocker, Roman

    2016-10-01

    Meaningful motion is an unambiguous biosignature, but because life in the Solar System is most likely to be microbial, the question is whether such motion may be detected effectively on the micrometer scale. Recent results on microbial motility in various Earth environments have provided insight into the physics and biology that determine whether and how microorganisms as small as bacteria and archaea swim, under which conditions, and at which speeds. These discoveries have not yet been reviewed in an astrobiological context. This paper discusses these findings in the context of Earth analog environments and environments expected to be encountered in the outer Solar System, particularly the jovian and saturnian moons. We also review the imaging technologies capable of recording motility of submicrometer-sized organisms and discuss how an instrument would interface with several types of sample-collection strategies.

  12. Where to Go: Breaking the Symmetry in Cell Motility

    PubMed Central

    2016-01-01

    Cell migration in the “correct” direction is pivotal for many biological processes. Although most work is devoted to its molecular mechanisms, the cell’s preference for one direction over others, thus overcoming intrinsic random motility, epitomizes a profound principle that underlies all complex systems: the choice of one axis, in structure or motion, from a uniform or symmetric set of options. Explaining directional motility by an external chemo-attractant gradient does not solve but only shifts the problem of causation: whence the gradient? A new study in PLOS Biology shows cell migration in a self-generated gradient, offering an opportunity to take a broader look at the old dualism of extrinsic instruction versus intrinsic symmetry-breaking in cell biology. PMID:27196433

  13. A Random Motility Assay Based on Image Correlation Spectroscopy

    PubMed Central

    Prummer, Michael; Kling, Dorothee; Trefzer, Vanessa; Enderle, Thilo; Zoffmann, Sannah; Prunotto, Marco

    2013-01-01

    We demonstrate the random motility (RAMOT) assay based on image correlation spectroscopy for the automated, label-free, high-throughput characterization of random cell migration. The approach is complementary to traditional migration assays, which determine only the collective net motility in a particular direction. The RAMOT assay is less demanding on image quality compared to single-cell tracking, does not require cell identification or trajectory reconstruction, and performs well on live-cell, time-lapse, phase contrast video microscopy of hundreds of cells in parallel. Effective diffusion coefficients derived from the RAMOT analysis are in quantitative agreement with Monte Carlo simulations and allowed for the detection of pharmacological effects on macrophage-like cells migrating on a planar collagen matrix. These results expand the application range of image correlation spectroscopy to multicellular systems and demonstrate a novel, to our knowledge, migration assay with little preparative effort. PMID:23746508

  14. Voltage- and calcium-dependent motility of saccular hair bundles

    NASA Astrophysics Data System (ADS)

    Quiñones, Patricia M.; Meenderink, Sebastiaan W. F.; Bozovic, Dolores

    2015-12-01

    Active bundle motility, which is hypothesized to supply feedback for mechanical amplification of signals, is thought to enhance sensitivity and sharpen tuning in vestibular and auditory organs. To study active hair bundle motility, we combined high-speed camera recordings of bullfrog sacculi, which were mounted in a two-compartment chamber, and voltage-clamp of the hair cell membrane potential. Using this paradigm, we measured three types of bundle motions: 1) spontaneous oscillations which can be analyzed to measure the physiological operating range of the transduction channel; 2) a sustained quasi-static movement of the bundle that depends on membrane potential; and 3) a fast, transient and asymmetric movement that resets the bundle position and depends on changes in the membrane potential. These data support a role for both calcium and voltage in the transduction-channel function.

  15. Biochemistry of actomyosin-dependent cell motility (a review).

    PubMed Central

    Korn, E D

    1978-01-01

    Actins and myosins similar to the major proteins of muscle are the major molecular components of intricate mechanochemical systems that perform numerous vital motility and structural functions in all eukaryotic cells. In this article, after a brief summary of the morphological distribution and ultrastructure of actin, myosin, and interrelated proteins of nonmuscle cells, our present knowledge of their biochemistry is critically appraised from the perspective that understanding complex cellular processes depends ultimately on the identification, purification, and biochemical characterization of the proteins involved. Although few conclusions are reached, possible molecular mechanisms for cellular regulation of actin polymerization, filament association, actomyosin ATPase activity, and mechanochemical coupling are discussed and a number of potentially fruitful directions for further research are suggested. These include comparative biochemical investigations and the study of the interaction of heterologous proteins, but particular emphasis is given to the need for quantitative studies at the molecular level of motility proteins purified from a single cellular source. PMID:147464

  16. Physical models of collective cell motility: from cell to tissue

    NASA Astrophysics Data System (ADS)

    Camley, B. A.; Rappel, W.-J.

    2017-03-01

    In this article, we review physics-based models of collective cell motility. We discuss a range of techniques at different scales, ranging from models that represent cells as simple self-propelled particles to phase field models that can represent a cell’s shape and dynamics in great detail. We also extensively review the ways in which cells within a tissue choose their direction, the statistics of cell motion, and some simple examples of how cell–cell signaling can interact with collective cell motility. This review also covers in more detail selected recent works on collective cell motion of small numbers of cells on micropatterns, in wound healing, and the chemotaxis of clusters of cells.

  17. Persistence-driven durotaxis: Generic, directed motility in rigidity gradients

    PubMed Central

    Novikova, Elizaveta A.; Raab, Matthew; Discher, Dennis E.; Storm, Cornelis

    2017-01-01

    Cells move differently on substrates with different elasticities. In particular, the persistence time of their motion is higher on stiffer substrates. We show that this behavior will result in a net transport of cells directed up a soft-to-stiff gradient. Using simple random walk models with controlled persistence and stochastic simulations, we characterize this propensity to move in terms of the durotactic index measured in experiments. A one-dimensional model captures the essential features of this motion and highlights the competition between diffusive spreading and linear, wavelike propagation. Since the directed motion is rooted in a non-directional change in the behavior of individual cells, the motility is a kinesis rather than a taxis. Persistence-driven durokinesis is generic and may be of use in the design of instructive environments for cells and other motile, mechanosensitive objects. PMID:28256894

  18. Microbial Morphology and Motility as Biosignatures for Outer Planet Missions.

    PubMed

    Nadeau, Jay; Lindensmith, Chris; Deming, Jody W; Fernandez, Vicente I; Stocker, Roman

    2016-10-01

    Meaningful motion is an unambiguous biosignature, but because life in the Solar System is most likely to be microbial, the question is whether such motion may be detected effectively on the micrometer scale. Recent results on microbial motility in various Earth environments have provided insight into the physics and biology that determine whether and how microorganisms as small as bacteria and archaea swim, under which conditions, and at which speeds. These discoveries have not yet been reviewed in an astrobiological context. This paper discusses these findings in the context of Earth analog environments and environments expected to be encountered in the outer Solar System, particularly the jovian and saturnian moons. We also review the imaging technologies capable of recording motility of submicrometer-sized organisms and discuss how an instrument would interface with several types of sample-collection strategies. Key Words: In situ measurement-Biosignatures-Microbiology-Europa-Ice. Astrobiology 16, 755-774.

  19. Motility contrast imaging of live porcine cumulus-oocyte complexes

    NASA Astrophysics Data System (ADS)

    An, Ran; Turek, John; Machaty, Zoltan; Nolte, David

    2013-02-01

    Freshly-harvested porcine oocytes are invested with cumulus granulosa cells in cumulus-oocyte complexes (COCs). The cumulus cell layer is usually too thick to image the living oocyte under a conventional microscope. Therefore, it is difficult to assess the oocyte viability. The low success rate of implantation is the main problem for in vitro fertilization. In this paper, we demonstrate our dynamic imaging technique called motility contrast imaging (MCI) that provides a non-invasive way to monitor the COCs before and after maturation. MCI shows a change of intracellular activity during oocyte maturation, and a measures dynamic contrast between the cumulus granulosa shell and the oocytes. MCI also shows difference in the spectral response between oocytes that were graded into quality classes. MCI is based on shortcoherence digital holography. It uses intracellular motility as the endogenous imaging contrast of living tissue. MCI presents a new approach for cumulus-oocyte complex assessment.

  20. Viscous inclusions in anisotropic materials: Theoretical development and perspective applications

    NASA Astrophysics Data System (ADS)

    Jiang, Dazhi

    2016-12-01

    that the conditions of scale separation are satisfied, the viscous inclusion theory forms the backbone of multiscale models for natural deformation and the accompanying texture and fabric development.

  1. Use of a mariner-based transposon mutagenesis system to isolate Clostridium perfringens mutants deficient in gliding motility.

    PubMed

    Liu, Hualan; Bouillaut, Laurent; Sonenshein, Abraham L; Melville, Stephen B

    2013-02-01

    Clostridium perfringens is an anaerobic Gram-positive pathogen that causes many human and animal diseases, including food poisoning and gas gangrene. C. perfringens lacks flagella but possesses type IV pili (TFP). We have previously shown that C. perfringens can glide across an agar surface in long filaments composed of individual bacteria attached end to end and that two TFP-associated proteins, PilT and PilC, are needed for this. To discover additional gene products that play a role in gliding, we developed a plasmid-based mariner transposon mutagenesis system that works effectively in C. perfringens. More than 10,000 clones were screened for mutants that lacked the ability to move away from the edge of a colony. Twenty-four mutants (0.24%) were identified that fit the criteria. The genes containing insertions that affected gliding motility fell into nine different categories. One gene, CPE0278, which encodes a homolog of the SagA cell wall-dependent endopeptidase, acquired distinct transposon insertions in two independent mutants. sagA mutants were unable to form filaments due to a complete lack of end-to-end connections essential for gliding motility. Complementation of the sagA mutants with a wild-type copy of the gene restored gliding motility. We constructed an in-frame deletion mutation in the sagA gene and found that this mutant had a phenotype similar to those of the transposon mutants. We hypothesize that the sagA mutant strains are unable to form the molecular complexes which are needed to keep the cells in an end-to-end orientation, leading to separation of daughter cells and the inability to carry out gliding motility.

  2. Motility modulation by the small non-coding RNA SroC in Salmonella Typhimurium.

    PubMed

    Fuentes, Danitza N; Calderón, Paulina F; Acuña, Lillian G; Rodas, Paula I; Paredes-Sabja, Daniel; Fuentes, Juan A; Gil, Fernando; Calderón, Iván L

    2015-09-01

    Bacterial regulatory networks of gene expression include the interaction of diverse types of molecules such as the small non-coding RNAs (sRNAs) and their cognate messenger RNAs (mRNAs). In this study, we demonstrated that the Salmonella Typhimurium sRNA SroC is significantly expressed between the late-exponential and stationary phase of growth in an rpoS-dependent manner. The expression of flagellar genes predicted as targets of this sRNA was quantitatively analyzed in both a ΔsroC mutant and a SroC-overexpressing (pSroC) strain. Deletion of sroC increased flagellar gene expression (i.e. flhBAE and fliE). Conversely, overexpression of SroC reduced flhBAE and fliE expression. These observations correlated with phenotypic evaluation of motility, where sroC deletion slightly increased motility, which in turn, was drastically reduced upon overexpression of SroC. The effects of deletion and overexpression of sroC in biofilm formation were also examined, where the ΔsroC and pSroC strains exhibited a reduced and increased ability to form biofilm, respectively. Furthermore, electron microscopy revealed that the wild-type strain overexpressing SroC had a non-flagellated phenotype. Taken together, our results showed that S. Typhimurium sRNA SroC modulates the flagellar synthesis by down-regulating the expression of flhBAE and fliE genes.

  3. The Rcs regulon in Proteus mirabilis: implications for motility, biofilm formation, and virulence.

    PubMed

    Howery, Kristen E; Clemmer, Katy M; Rather, Philip N

    2016-11-01

    The overall role of the Rcs phosphorelay in Proteus mirabilis is largely unknown. Previous work had demonstrated that the Rcs phosphorelay represses the flhDC operon and activates the minCDE cell division inhibition system. To identify additional cellular functions regulated by the Rcs phosphorelay, an analysis of RNA-seq data was undertaken. In this report, the results of the RNA-sequencing are discussed with an emphasis on the predicted roles of the Rcs phosphorelay in swarmer cell differentiation, motility, biofilm formation, and virulence. RcsB is shown to activate genes important for differentiation and fimbriae formation, while repressing the expression of genes important for motility and virulence. Additionally, to follow up on the RNA-Seq data, we demonstrate that an rcsB mutant is deficient in its ability to form biofilm and exhibits enhanced virulence in a Galleria mellonella waxworm model. Overall, these results indicate the Rcs regulon in P. mirabilis extends beyond flagellar genes to include those involved in biofilm formation and virulence. Furthermore, the information presented in this study may provide clues to additional roles of the Rcs phosphorelay in other members of the Enterobacteriaceae.

  4. Buoyant plumes from solute gradients generated by non-motile Escherichia coli

    NASA Astrophysics Data System (ADS)

    Benoit, M. R.; Brown, R. B.; Todd, P.; Nelson, E. S.; Klaus, D. M.

    2008-12-01

    The effect of hydrodynamic mixing in bacterial populations due to bacterial chemotaxis is a well-described phenomenon known as bioconvection. Here we report the observation of buoyant plumes that result in hydrodynamic mixing, but in contrast to bioconvection the plumes form in the absence of bacterial motility. We propose that the buoyant flow originates from solute gradients created by bacterial metabolism, similar to solute-induced buoyant flow around growing protein crystals. In our experiments, metabolically-active non-motile Escherichia coli were layered along the bottom of flat-bottomed containers. The E. coli consumed glucose in the medium creating a lighter fluid beneath a heavier fluid. The situation is an example of Rayleigh-Taylor instability, in which a lighter fluid pushes on a heavier one. We developed a numerical model to study the effect of E. coli nutrient consumption and by-product excretion on extracellular solute gradients. The model solutions showed reduced-density fluid along the bottom of the fluid domain leading to buoyant plumes, which were qualitatively similar to the experimental plumes. We also used scaling analyses to study the dependence of plume formation on container size and cell size, and to investigate the effect of reduced gravity, such as the microgravity conditions encountered during spaceflight.

  5. Evaporation-driven convection observed in a suspension of non-motile bacteria

    NASA Astrophysics Data System (ADS)

    Dunstan, Jocelyn; Lee, Kyoung Jin; Park, Simon; Goldstein, Raymond E.

    2015-03-01

    We report a novel form of convection in a suspension of non-motile bioluminescent bacteria. The patterns appear like those of conventional bioconvection driven by oxygentaxis, yet the bacteria are observed to have limited if any motility. While the phenomenon also resembles chemo-convection, in which a chemical reaction (or metabolic activity) alters the local buoyancy balance at the air-water interface, the convention actually derives from evaporation of the salty bacterial growth medium. We corroborate this through control experiments using polystyrene beads in pure and salty water, and establish that there is a threshold of salt concentration needed to observe plumes. The dynamics of the plumes is rich, with striking coalescence events and a complex internal structure. A mathematical model is formulated for the process and studied analytically and numerically, reproducing most of the observed experimental features. Evaporation-driven convection on the millimeter scale has not been studied extensively and its effect may have been underestimated in a variety of contexts. It may naturally occur in marine settings.

  6. A bacterial extracellular DNA inhibits settling of motile progeny cells within a biofilm

    PubMed Central

    Berne, Cécile; Kysela, David T.; Brun, Yves V.

    2010-01-01

    In natural systems, bacteria form complex, surface-attached communities known as biofilms. This lifestyle presents numerous advantages compared to unattached or planktonic life, such as exchange of nutrients, protection from environmental stresses and increased tolerance to biocides. Despite such benefits, dispersal also plays an important role in escaping deteriorating environments and in successfully colonizing favorable, unoccupied habitat patches. The α-proteobacterium Caulobacter crescentus produces a motile swarmer cell and a sessile stalked cell at each cell division. We show here that C. crescentus extracellular DNA (eDNA) inhibits the ability of its motile cell type to settle in a biofilm. eDNA binds to the polar holdfast, an adhesive structure required for permanent surface attachment and biofilm formation, thereby inhibiting cell attachment. Since stalked cells associate tightly with the biofilm through their holdfast, we hypothesize that this novel mechanism acts on swarmer cells born in a biofilm, where eDNA can accumulate to a sufficient concentration to inhibit their ability to settle. By targeting a specific cell type in a biofilm, this mechanism modulates biofilm development and promotes dispersal without causing a potentially undesirable dissolution of the existing biofilm. PMID:20598083

  7. Vibrio cholerae use pili and flagella synergistically to effect motility switching and conditional surface attachment

    NASA Astrophysics Data System (ADS)

    Utada, Andrew S.; Bennett, Rachel R.; Fong, Jiunn C. N.; Gibiansky, Maxsim L.; Yildiz, Fitnat H.; Golestanian, Ramin; Wong, Gerard C. L.

    2014-09-01

    We show that Vibrio cholerae, the causative agent of cholera, use their flagella and mannose-sensitive hemagglutinin (MSHA) type IV pili synergistically to switch between two complementary motility states that together facilitate surface selection and attachment. Flagellar rotation counter-rotates the cell body, causing MSHA pili to have periodic mechanical contact with the surface for surface-skimming cells. Using tracking algorithms at 5 ms resolution we observe two motility behaviours: ‘roaming', characterized by meandering trajectories, and ‘orbiting’, characterized by repetitive high-curvature orbits. We develop a hydrodynamic model showing that these phenotypes result from a nonlinear relationship between trajectory shape and frictional forces between pili and the surface: strong pili-surface interactions generate orbiting motion, increasing the local bacterial loiter time. Time-lapse imaging reveals how only orbiting mode cells can attach irreversibly and form microcolonies. These observations suggest that MSHA pili are crucial for surface selection, irreversible attachment, and ultimately microcolony formation.

  8. An Outer Arm Dynein Conformational Switch Is Required for Metachronal Synchrony of Motile Cilia in Planaria

    PubMed Central

    Rompolas, Panteleimon; Patel-King, Ramila S.

    2010-01-01

    Motile cilia mediate the flow of mucus and other fluids across the surface of specialized epithelia in metazoans. Efficient clearance of peri-ciliary fluids depends on the precise coordination of ciliary beating to produce metachronal waves. The role of individual dynein motors and the mechanical feedback mechanisms required for this process are not well understood. Here we used the ciliated epithelium of the planarian Schmidtea mediterranea to dissect the role of outer arm dynein motors in the metachronal synchrony of motile cilia. We demonstrate that animals that completely lack outer dynein arms display a significant decline in beat frequency and an inability of cilia to coordinate their oscillations and form metachronal waves. Furthermore, lack of a key mechanosensitive regulatory component (LC1) yields a similar phenotype even though outer arms still assemble in the axoneme. The lack of metachrony was not due simply to a decrease in ciliary beat frequency, as reducing this parameter by altering medium viscosity did not affect ciliary coordination. In addition, we did not observe a significant temporal variability in the beat cycle of impaired cilia. We propose that this conformational switch provides a mechanical feedback system within outer arm dynein that is necessary to entrain metachronal synchrony. PMID:20844081

  9. Mitochondrial organization and motility probed by two-photon microscopy in cultured mouse brainstem neurons

    SciTech Connect

    Mueller, Michael . E-mail: mike@neuro-physiol.med.uni-goettingen.de; Mironov, Sergej L.; Ivannikov, Maxim V.; Schmidt, Joerg; Richter, Diethelm W.

    2005-02-01

    Two-photon microscopy of rhodamine 123-labeled mitochondria revealed that mitochondria of neurons cultured from mouse respiratory center form functionally coupled, dynamically organized aggregates such as chains and clusters, while single mitochondria were rarely seen. Mitochondrial chain structures predominate in dendrites, while irregularly shaped mitochondrial clusters are mostly found in the soma. Both types of mitochondrial structures showed chaotic Brownian motions and the mitochondrial chains also revealed well-directed movements. The latter dislocations were arrested upon mitochondrial depolarization or blockade of mitochondrial ATP synthesis. Depolymerization of microtubules by colchicine or nocodazole or inhibition of protein phosphatases by calyculin A disrupted mitochondrial chains and the mitochondria accumulated in the soma. Forskolin and IBMX reversibly blocked directed movements of mitochondria, but did not affect their overall spatial distribution. Thus, protein phosphorylation seems to control both mitochondrial transport and organization. Protein phosphorylation downstream of enhanced cytosolic cAMP levels apparently regulates the transition from motile to non-motile mitochondria, while phosphorylation resulting from inhibition of types 1 and 2A protein phosphatases massively disturbs mitochondrial organization. The complex phosphorylation processes seem to control the close interaction of mitochondria and cytoskeleton which may guarantee that mitochondria are immobilized at energetic hot spots and rearranged in response to changes in local energy demands.

  10. Exploring the link between gastric motility and intragastric drug distribution in man.

    PubMed

    Van Den Abeele, Jens; Brouwers, Joachim; Tack, Jan; Augustijns, Patrick

    2017-03-01

    In drug development, the stomach is often considered to be a simple, one-compartmental organ, a waiting room for transfer of an orally administered dosage form to the duodenum. However, factors such as gastric acidity and hydrodynamics in the gastric environment may influence drug disposition. Although a link between gastrointestinal drug behaviour and gastric motility has often been hypothesized, they have not been simultaneously investigated in humans yet. In this proof-of-concept study, the combination of a well-established intraluminal sampling technique with high-resolution manometric measurements in the gastrointestinal tract was evaluated. This new combination of in vivo techniques proved to be feasible from a practical point of view and yielded valuable additional information regarding intraluminal drug behaviour. As a first application, the link between fasted state gastric motility and (in)homogeneous distribution of an orally administered drug in the stomach was investigated in healthy subjects. To this end, drug concentrations were measured in different regions of the stomach after oral administration of a commercially available drug product (Gabbroral®, 250mg paromomycin) during a specific period of gastric contractile activity. A clear trend towards better mixing of an orally administered drug with gastric contents was observed when dosed in the presence of gastric contractions, resulting in a more homogeneous distribution of the drug throughout the stomach compared to dosing in the absence of gastric contractions.

  11. An outer arm Dynein conformational switch is required for metachronal synchrony of motile cilia in planaria.

    PubMed

    Rompolas, Panteleimon; Patel-King, Ramila S; King, Stephen M

    2010-11-01

    Motile cilia mediate the flow of mucus and other fluids across the surface of specialized epithelia in metazoans. Efficient clearance of peri-ciliary fluids depends on the precise coordination of ciliary beating to produce metachronal waves. The role of individual dynein motors and the mechanical feedback mechanisms required for this process are not well understood. Here we used the ciliated epithelium of the planarian Schmidtea mediterranea to dissect the role of outer arm dynein motors in the metachronal synchrony of motile cilia. We demonstrate that animals that completely lack outer dynein arms display a significant decline in beat frequency and an inability of cilia to coordinate their oscillations and form metachronal waves. Furthermore, lack of a key mechanosensitive regulatory component (LC1) yields a similar phenotype even though outer arms still assemble in the axoneme. The lack of metachrony was not due simply to a decrease in ciliary beat frequency, as reducing this parameter by altering medium viscosity did not affect ciliary coordination. In addition, we did not observe a significant temporal variability in the beat cycle of impaired cilia. We propose that this conformational switch provides a mechanical feedback system within outer arm dynein that is necessary to entrain metachronal synchrony.

  12. Buoyant plumes from solute gradients generated by non-motile Escherichia coli.

    PubMed

    Benoit, M R; Brown, R B; Todd, P; Nelson, E S; Klaus, D M

    2008-12-10

    The effect of hydrodynamic mixing in bacterial populations due to bacterial chemotaxis is a well-described phenomenon known as bioconvection. Here we report the observation of buoyant plumes that result in hydrodynamic mixing, but in contrast to bioconvection the plumes form in the absence of bacterial motility. We propose that the buoyant flow originates from solute gradients created by bacterial metabolism, similar to solute-induced buoyant flow around growing protein crystals. In our experiments, metabolically-active non-motile Escherichia coli were layered along the bottom of flat-bottomed containers. The E. coli consumed glucose in the medium creating a lighter fluid beneath a heavier fluid. The situation is an example of Rayleigh-Taylor instability, in which a lighter fluid pushes on a heavier one. We developed a numerical model to study the effect of E. coli nutrient consumption and by-product excretion on extracellular solute gradients. The model solutions showed reduced-density fluid along the bottom of the fluid domain leading to buoyant plumes, which were qualitatively similar to the experimental plumes. We also used scaling analyses to study the dependence of plume formation on container size and cell size, and to investigate the effect of reduced gravity, such as the microgravity conditions encountered during spaceflight.

  13. Earthquake-like dynamics in Myxococcus xanthus social motility

    PubMed Central

    Gibiansky, Maxsim L.; Hu, Wei; Dahmen, Karin A.; Shi, Wenyuan; Wong, Gerard C. L.

    2013-01-01

    Myxococcus xanthus is a bacterium capable of complex social organization. Its characteristic social (“S”)-motility mechanism is mediated by type IV pili (TFP), linear actuator appendages that propel the bacterium along a surface. TFP are known to bind to secreted exopolysaccharides (EPS), but it is unclear how M. xanthus manages to use the TFP-EPS technology common to many bacteria to achieve its unique coordinated multicellular movements. We examine M. xanthus S-motility, using high-resolution particle-tracking algorithms, and observe aperiodic stick–slip movements. We show that they are not due to chemotaxis, but are instead consistent with a constant TFP-generated force interacting with EPS, which functions both as a glue and as a lubricant. These movements are quantitatively homologous to the dynamics of earthquakes and other crackling noise systems. These systems exhibit critical behavior, which is characterized by a statistical hierarchy of discrete “avalanche” motions described by a power law distribution. The measured critical exponents from M. xanthus are consistent with mean field theoretical models and with other crackling noise systems, and the measured Lyapunov exponent suggests the existence of highly branched EPS. Such molecular architectures, which are common for efficient lubricants but rare in bacterial EPS, may be necessary for S-motility: We show that the TFP of leading “locomotive” cells initiate the collective motion of follower cells, indicating that lubricating EPS may alleviate the force generation requirements on the lead cell and thus make S-motility possible. PMID:23341622

  14. Spontaneous redistribution of surface immunoglobulin in the motile B lymphocyte

    PubMed Central

    1976-01-01

    This paper reports that B cells undergoing translatory motion spontaneously segregate their surface Ig to one portion of their plasma membrane. The spontaneous redistribution of surface Ig was found to be: (a) selective, concanavalin A-dependent on translatory motion and energy metabolism. Abundant B cells undergoing motility were found after cultures in lipopolysaccharide or trypsin, or after brief exposure to cholinergic drugs. PMID:1087328

  15. The Semen pH Affects Sperm Motility and Capacitation.

    PubMed

    Zhou, Ji; Chen, Li; Li, Jie; Li, Hongjun; Hong, Zhiwei; Xie, Min; Chen, Shengrong; Yao, Bing

    2015-01-01

    As the chemical environment of semen can have a profound effect on sperm quality, we examined the effect of pH on the motility, viability and capacitation of human sperm. The sperm in this study was collected from healthy males to avoid interference from other factors. The spermatozoa cultured in sperm nutrition solution at pH 5.2, 6.2, 7.2 and 8.2 were analyzed for sperm total motility, progressive motility (PR), hypo-osmotic swelling (HOS) rate, and sperm penetration. Our results showed that these parameters were similar in pH 7.2 and 8.2 sperm nutrition solutions, but decreased in pH 5.2 and 6.2 solutions. The HOS rate exhibited positive correlation with the sperm total motility and PR. In addition, the sperm Na(+)/K(+)-ATPase activity at different pHs was measured, and the enzyme activity was significantly lower in pH 5.2 and 6.2 media, comparing with that in pH 8.2 and pH 7.2 solutions. Using flow cytometry (FCM) and laser confocal scanning microscopy (LCSM) analysis, the intracellular Ca2(+ )concentrations of sperm cultured in sperm capacitation solution at pH 5.2, 6.2, 7.2 and 8.2 were determined. Compared with that at pH 7.2, the mean fluorescence intensity of sperm in pH 5.2 and 6.2 media decreased significantly, while that of pH 8.2 group showed no difference. Our results suggested that the declined Na(+)/K(+)-ATPase activity at acidic pHs result in decreased sperm movement and capacitation, which could be one of the mechanisms of male infertility.

  16. Effect of pre-freezing conditions on the progressive motility recovery rate of human frozen spermatozoa.

    PubMed

    Zhang, X; Zhou, Y; Xia, W; Wu, H; Yao, K; Liu, H; Xiong, C

    2012-10-01

    We evaluated the effects of sperm concentration, progressive motility, sperm morphology, duration of abstinence and collection season on the progressive motility recovery rate of human frozen spermatozoa to identify characteristics that predict the progressive motility recovery rate of human frozen spermatozoa and improve the protocol for sperm collecting in sperm banks. A total of 14 190 semen samples donated at Zhejiang human sperm bank of China between September 2006 and June 2011 were collected from 1624 donors. Semen was evaluated according to WHO standard procedures for sperm concentration. Progressive motility, sperm morphology, ejaculate collection season and abstinence time were recorded. After freezing and thawing, the progressive motility was assessed. Results showed that sperm concentration, progressive motility and normal morphology were significantly associated with the progressive motility recovery rate of human frozen spermatozoa. In addition, the abstinence time and collection season also significantly affected progressive motility recovery rate. Our results indicated that sperm concentration, progressive motility and normal morphology could be valuable in predicting the progressive motility recovery rate of human frozen spermatozoa. As such, progressive motility recovery may be improved by donating semen when abstinent for 3-5 days and during seasons other than summer.

  17. Actin-Based Motility of Intracellular Microbial Pathogens

    PubMed Central

    Goldberg, Marcia B.

    2001-01-01

    A diverse group of intracellular microorganisms, including Listeria monocytogenes, Shigella spp., Rickettsia spp., and vaccinia virus, utilize actin-based motility to move within and spread between mammalian host cells. These organisms have in common a pathogenic life cycle that involves a stage within the cytoplasm of mammalian host cells. Within the cytoplasm of host cells, these organisms activate components of the cellular actin assembly machinery to induce the formation of actin tails on the microbial surface. The assembly of these actin tails provides force that propels the organisms through the cell cytoplasm to the cell periphery or into adjacent cells. Each of these organisms utilizes preexisting mammalian pathways of actin rearrangement to induce its own actin-based motility. Particularly remarkable is that while all of these microbes use the same or overlapping pathways, each intercepts the pathway at a different step. In addition, the microbial molecules involved are each distinctly different from the others. Taken together, these observations suggest that each of these microbes separately and convergently evolved a mechanism to utilize the cellular actin assembly machinery. The current understanding of the molecular mechanisms of microbial actin-based motility is the subject of this review. PMID:11729265

  18. EFFECTS OF METHYLNALTREXONE ON GUINEA PIG GASTROINTESTINAL MOTILITY

    PubMed Central

    Anselmi, Laura; Huynh, Jennifer; Vegezzi, Gaia; Sternini, Catia

    2013-01-01

    The purpose of the present study was to compare the effects of methylnaltrexone (MNTX), a peripherally acting μ opioid receptor (μOR) antagonist, on gastrointestinal (GI) motility in naïve vs. opiate-chronically treated guinea pigs in vitro and in vivo. We have used the electrically stimulated muscle twitch contractions of longitudinal muscle-myenteric plexus (LMMP) preparations and total GI transit as measure of GI motility. In LMMP preparations of naïve guinea pigs, MNTX (1–30 μM) induced a significant, dose-response reduction of morphine-induced inhibition of electrically stimulated muscle twitch contractions, with an IC50 of 9.4 10−8M. By contrast, MNTX abolished the inhibitory effect of acute morphine at any concentration tested (1–30 μM) in the guinea pigs chronically treated with opiates. In vivo, MNTX (10–50 mg s.c.) did not affect GI transit in naïve guinea pigs when administered acutely or for 5 consecutive days, but reversed the GI transit delay induced by chronic morphine treatment. These findings show that MNTX is effective in reversing opiate-induced inhibition of GI motility acting at peripheral μORs, but does not exert a pharmacologic effect on GI transit in the absence of opiate stimulation. PMID:23361094

  19. Actin-based motility propelled by molecular motors

    NASA Astrophysics Data System (ADS)

    Upadyayula, Sai Pramod; Rangarajan, Murali

    2012-09-01

    Actin-based motility of Listeria monocytogenes propelled by filament end-tracking molecular motors has been simulated. Such systems may act as potential nanoscale actuators and shuttles useful in sorting and sensing biomolecules. Filaments are modeled as three-dimensional elastic springs distributed on one end of the capsule and persistently attached to the motile bacterial surface through an end-tracking motor complex. Filament distribution is random, and monomer concentration decreases linearly as a function of position on the bacterial surface. Filament growth rate increases with monomer concentration but decreases with the extent of compression. The growing filaments exert push-pull forces on the bacterial surface. In addition to forces, torques arise due to two factors—distribution of motors on the bacterial surface, and coupling of torsion upon growth due to the right-handed helicity of F-actin—causing the motile object to undergo simultaneous translation and rotation. The trajectory of the bacterium is simulated by performing a force and torque balance on the bacterium. All simulations use a fixed value of torsion. Simulations show strong alignment of the filaments and the long axis of the bacterium along the direction of motion. In the absence of torsion, the bacterial surface essentially moves along the direction of the long axis. When a small amount of the torsion is applied to the bacterial surface, the bacterium is seen to move in right-handed helical trajectories, consistent with experimental observations.

  20. Gains of Bacterial Flagellar Motility in a Fungal World

    PubMed Central

    Pion, Martin; Bshary, Redouan; Bindschedler, Saskia; Filippidou, Sevasti; Wick, Lukas Y.; Job, Daniel

    2013-01-01

    The maintenance of energetically costly flagella by bacteria in non-water-saturated media, such as soil, still presents an evolutionary conundrum. Potential explanations have focused on rare flooding events allowing dispersal. Such scenarios, however, overlook bacterial dispersal along mycelia as a possible transport mechanism in soils. The hypothesis tested in this study is that dispersal along fungal hyphae may lead to an increase in the fitness of flagellated bacteria and thus offer an alternative explanation for the maintenance of flagella even in unsaturated soils. Dispersal along fungal hyphae was shown for a diverse array of motile bacteria. To measure the fitness effect of dispersal, additional experiments were conducted in a model system mimicking limited dispersal, using Pseudomonas putida KT2440 and its nonflagellated (ΔfliM) isogenic mutant in the absence or presence of Morchella crassipes mycelia. In the absence of the fungus, flagellar motility was beneficial solely under conditions of water saturation allowing dispersal, while under conditions limiting dispersal, the nonflagellated mutant exhibited a higher level of fitness than the wild-type strain. In contrast, in the presence of a mycelial network under conditions limiting dispersal, the flagellated strain was able to disperse using the mycelial network and had a higher level of fitness than the mutant. On the basis of these results, we propose that the benefit of mycelium-associated dispersal helps explain the persistence of flagellar motility in non-water-saturated environments. PMID:23995942

  1. Gains of bacterial flagellar motility in a fungal world.

    PubMed

    Pion, Martin; Bshary, Redouan; Bindschedler, Saskia; Filippidou, Sevasti; Wick, Lukas Y; Job, Daniel; Junier, Pilar

    2013-11-01

    The maintenance of energetically costly flagella by bacteria in non-water-saturated media, such as soil, still presents an evolutionary conundrum. Potential explanations have focused on rare flooding events allowing dispersal. Such scenarios, however, overlook bacterial dispersal along mycelia as a possible transport mechanism in soils. The hypothesis tested in this study is that dispersal along fungal hyphae may lead to an increase in the fitness of flagellated bacteria and thus offer an alternative explanation for the maintenance of flagella even in unsaturated soils. Dispersal along fungal hyphae was shown for a diverse array of motile bacteria. To measure the fitness effect of dispersal, additional experiments were conducted in a model system mimicking limited dispersal, using Pseudomonas putida KT2440 and its nonflagellated (ΔfliM) isogenic mutant in the absence or presence of Morchella crassipes mycelia. In the absence of the fungus, flagellar motility was beneficial solely under conditions of water saturation allowing dispersal, while under conditions limiting dispersal, the nonflagellated mutant exhibited a higher level of fitness than the wild-type strain. In contrast, in the presence of a mycelial network under conditions limiting dispersal, the flagellated strain was able to disperse using the mycelial network and had a higher level of fitness than the mutant. On the basis of these results, we propose that the benefit of mycelium-associated dispersal helps explain the persistence of flagellar motility in non-water-saturated environments.

  2. Current concepts of mechanical and neural factors in ocular motility

    PubMed Central

    Demer, Joseph L.

    2007-01-01

    Purpose of review The oculomotor periphery was classically regarded as a simple mechanism executing complex behaviors specified explicitly by neural commands. A competing view has emerged that many important aspects of ocular motility are properties of the extraocular muscles and their associated connective tissue pulleys. This review considers current concepts regarding aspects of ocular motility that are mechanically determined versus those that are specified explicitly as innervation. Recent findings While it was established several years ago that the rectus extraocular muscles have connective tissue pulleys, recent functional imaging and histology has suggested that the rectus pulley array constitutes an inner mechanism, analogous to a gimbal, that is rotated torsionally around the orbital axis by an outer mechanism driven by the oblique extraocular muscles. This arrangement may account mechanically for several commutative aspects of ocular motor control, including Listing’s Law, yet permits implementation of non-commutative motility. Recent human behavioral studies, as well as neurophysiology in monkeys, are consistent with implementation of Listing’s Law in the oculomotor periphery, rather than centrally. Summary Varied evidence now strongly supports the conclusion that Listing’s Law and other important ocular kinematics are mechanically determined. This finding implies more limited possibilities for neural adaptation to some ocular motor pathologies, but indicates possibilities for surgical treatments. PMID:16415671

  3. Drosophila Sperm Motility in the Reproductive Tract1

    PubMed Central

    Yang, Yong; Lu, Xiangyi

    2011-01-01

    Motile cilia and flagella exhibit many waveforms as outputs of dynein activation sequences on the highly conserved axoneme. Motility change of sperm in the reproductive tract is difficult to study and remains an important area of investigation. Sperm typically execute a sinusoidal waveform. Increased viscosity in the medium induces somewhat unusual arc-line and helical waveforms in some sperm. However, whether the latter two waveforms occur in vivo is not known. Using green fluorescence protein imaging, we show that Drosophila sperm in the uterus move in circular foci via arc-line waves, predominantly in a tail-leading orientation. From the uterus, a small fraction of the sperm enters the seminal receptacle (SR) in parallel formations. After sperm storage and coincident with fertilization of the egg, the sperm exit the SR via head-leading helical waves. Consistent with the observed bidirectional movements, the sperm show the ability to propagate both base-to-tip and tip-to-base flagellar waves. Numerous studies have shown that sperm motility is regulated by intraflagellar calcium concentrations; in particular, the Pkd2 calcium channel has been shown to affect sperm storage. Our analyses here suggest that Pkd2 is required for the sperm to adopt the correct waveform and movement orientation during SR entry. A working model for the sperm's SR entry movement is proposed. PMID:21293028

  4. Genetics Home Reference: inclusion body myopathy 2

    MedlinePlus

    ... Conditions inclusion body myopathy 2 inclusion body myopathy 2 Enable Javascript to view the expand/collapse boxes. ... Open All Close All Description Inclusion body myopathy 2 is a condition that primarily affects skeletal muscles , ...

  5. Sperm motility-initiating substance in newt egg-jelly induces differential initiation of sperm motility based on sperm intracellular calcium levels.

    PubMed

    Watanabe, Akihiko; Takayama-Watanabe, Eriko; Vines, Carol A; Cherr, Gary N

    2011-01-01

    Sperm motility-initiating substance (SMIS), a novel motility inducer from newt egg-jelly, is activated by the release from associated jelly substances at the beginning of internal fertilization and affects female-stored sperm. We examined motility initiation kinetics of newt sperm in response to SMIS by monitoring the changes of sperm intracellular calcium ([Ca²(+)](i)). In quiescent non-motile sperm loaded with the Ca²(+) indicator Fluo-4, intracellular free Ca²(+) was observed around mitochondria using confocal scanning laser microscopy. A slight increase in [Ca²(+)](i) occurred simultaneously and transiently at motility initiation in sperm treated with either heated jelly extract (hJE) containing activated SMIS, or a low osmotic solution, which naturally initiates motility in externally-fertilizing amphibians and can initiate motility in urodele sperm. When the increase of [Ca²(+)](i) at motility-initiation was monitored using spectrofluorometry, large increases in [Ca²(+)](i) occurred immediately in the low osmotic solution and within 1.5 min in the hJE. In the intact jelly extract (no heating), small increases of [Ca²(+)](i) irregularly occurred from around 1 min and for about 4 min, during which motility was differentially initiated among sperm. These results indicate that the SMIS induces differential initiation of sperm motility depending on the activational states of the SMIS and its overall activity. The motility initiation in the jelly extract was delayed in sperm whose intracellular Ca²(+) had been chelated with BAPTA-AM. The relative levels of [Ca²(+)](i) were variable with a mean of 414 ± 256 nmol/L among resting sperm, suggesting that the level of [Ca²(+)](i) in the resting sperm modulates the responsiveness to the SMIS.

  6. A convex hull inclusion test.

    PubMed

    Bailey, T; Cowles, J

    1987-02-01

    A new characterization of the interior of the convex hull of a finite point set is given. An inclusion test based on this characterization is, on average, almost linear in the number of points times the dimensionality.

  7. Inclusion-Body Myositis: Diagnosis

    MedlinePlus

    ... Make a Donation Matching Gifts Legacy Gifts Product Donations Partner Become an MDA Partner Meet our Partners How to Get Involved Donate Inclusion-Body Myositis (IBM) Share print email share facebook twitter ...

  8. Characterization of Pro-Inflammatory Flagellin Proteins Produced by Lactobacillus ruminis and Related Motile Lactobacilli

    PubMed Central

    Neville, B. Anne; Forde, Brian M.; Claesson, Marcus J.; Darby, Trevor; Coghlan, Avril; Nally, Kenneth; Ross, R. Paul; O’Toole, Paul W.

    2012-01-01

    Lactobacillus ruminis is one of at least twelve motile but poorly characterized species found in the genus Lactobacillus. Of these, only L. ruminis has been isolated from mammals, and this species may be considered as an autochthonous member of the gastrointestinal microbiota of humans, pigs and cows. Nine L. ruminis strains were investigated here to elucidate the biochemistry and genetics of Lactobacillus motility. Six strains isolated from humans were non-motile while three bovine isolates were motile. A complete set of flagellum biogenesis genes was annotated in the sequenced genomes of two strains, ATCC25644 (human isolate) and ATCC27782 (bovine isolate), but only the latter strain produced flagella. Comparison of the L. ruminis and L. mali DSM20444T motility loci showed that their genetic content and gene-order were broadly similar, although the L. mali motility locus was interrupted by an 11.8 Kb region encoding rhamnose utilization genes that is absent from the L. ruminis motility locus. Phylogenetic analysis of 39 motile bacteria indicated that Lactobacillus motility genes were most closely related to those of motile carnobacteria and enterococci. Transcriptome analysis revealed that motility genes were transcribed at a significantly higher level in motile L. ruminis ATCC27782 than in non-motile ATCC25644. Flagellin proteins were isolated from L. ruminis ATCC27782 and from three other Lactobacillus species, while recombinant flagellin of aflagellate L. ruminis ATCC25644 was expressed and purified from E. coli. These native and recombinant Lactobacillus flagellins, and also flagellate L. ruminis cells, triggered interleukin-8 production in cultured human intestinal epithelial cells in a manner suppressed by short interfering RNA directed against Toll-Like Receptor 5. This study provides genetic, transcriptomic, phylogenetic and immunological insights into the trait of flagellum-mediated motility in the lactobacilli. PMID:22808200

  9. Resource level affects relative performance of the two motility systems of Myxococcus xanthus.

    PubMed

    Hillesland, Kristina L; Velicer, Gregory J

    2005-05-01

    The adventurous (A) and social (S) motility systems of the microbial predator Myxococcus xanthus show differential swarming performance on distinct surface types. Under standard laboratory conditions, A-motility performs well on hard agar but poorly on soft agar, whereas the inverse pattern is shown by S-motility. These properties may allow M. xanthus to swarm effectively across a greater diversity of natural surfaces than would be possible with one motility system alone. Nonetheless, the range of ecological conditions under which dual motility enhances effective swarming across distinct surfaces and how ecological parameters affect the complementarity of A-motility and S-motility remain unclear. Here we have examined the role of nutrient concentration in determining swarming patterns driven by dual motility on distinct agar surfaces, as well as the relative contributions of A-motility and S-motility to these patterns. Swarm expansion rates of dually motile (A+S+), solely A-motile (A+S-), and solely S-motile (A-S+) strains were compared on hard and soft agar across a wide range of casitone concentrations. At low casitone concentrations (0-0.1%), swarming on soft agar driven by S-motility is very poor, and is significantly slower than swarming on hard agar driven by A-motility. This reverses at high casitone concentration (1-3.2%) such that swarming on soft agar is much faster than swarming on hard agar. This pattern greatly constrained the ability of M. xanthus to encounter patches of prey bacteria on a soft agar surface when nutrient levels between the patches were low. The swarming patterns of a strain that is unable to produce extracellular fibrils indicate that these appendages are responsible for the elevated swarming of S-motility at high resource levels. Together, these data suggest that large contributions by S-motility to predatory swarming in natural soils may be limited to soft, wet, high-nutrient conditions that may be uncommon. Several likely benefits

  10. Motility at the origin of life: its characterization and a model.

    PubMed

    Froese, Tom; Virgo, Nathaniel; Ikegami, Takashi

    2014-01-01

    Due to recent advances in synthetic biology and artificial life, the origin of life is currently a hot topic of research. We review the literature and argue that the two traditionally competing replicator-first and metabolism-first approaches are merging into one integrated theory of individuation and evolution. We contribute to the maturation of this more inclusive approach by highlighting some problematic assumptions that still lead to an ximpoverished conception of the phenomenon of life. In particular, we argue that the new consensus has so far failed to consider the relevance of intermediate time scales. We propose that an adequate theory of life must account for the fact that all living beings are situated in at least four distinct time scales, which are typically associated with metabolism, motility, development, and evolution. In this view, self-movement, adaptive behavior, and morphological changes could have already been present at the origin of life. In order to illustrate this possibility, we analyze a minimal model of lifelike phenomena, namely, of precarious, individuated, dissipative structures that can be found in simple reaction-diffusion systems. Based on our analysis, we suggest that processes on intermediate time scales could have already been operative in prebiotic systems. They may have facilitated and constrained changes occurring in the faster- and slower-paced time scales of chemical self-individuation and evolution by natural selection, respectively.

  11. Sperm motility of externally fertilizing fish and amphibians.

    PubMed

    Browne, R K; Kaurova, S A; Uteshev, V K; Shishova, N V; McGinnity, D; Figiel, C R; Mansour, N; Agney, D; Wu, M; Gakhova, E N; Dzyuba, B; Cosson, J

    2015-01-01

    We review the phylogeny, sperm competition, morphology, physiology, and fertilization environments of the sperm of externally fertilizing fish and amphibians. Increased sperm competition in both fish and anurans generally increases sperm numbers, sperm length, and energy reserves. The difference between the internal osmolarity and iconicity of sperm cells and those of the aquatic medium control the activation, longevity, and velocity of sperm motility. Hypo-osmolarity of the aquatic medium activates the motility of freshwater fish and amphibian sperm and hyperosmolarity activates the motility of marine fish sperm. The average longevity of the motility of marine fish sperm (~550 seconds) was significantly (P < 0.05) greater than that of freshwater fish sperm (~150 seconds), with the longevities of both marine and freshwater fish being significantly (P < 0.05) lower than that of anuran sperm (~4100 seconds). The average velocity of anuran sperm (25 μm/s) was significantly (P < 0.05) lower than that of marine fish (140 μm/s) or freshwater fish (135 μm/s) sperm. The longevity of the sperm of giant salamanders (Cryptobranchoidea) of approximately 600 seconds was greater than that of freshwater fish sperm but much lower than anuran sperm. Our research and information from the literature showed that higher osmolarities promote greater longevity in anuran sperm, and some freshwater fish sperm, and that anuran and cryptobranchid sperm maintained membrane integrity long after the cessation of motility, demonstrating a preferential sharing of energy reserves toward the maintenance of membrane integrity. The maintenance of the membrane integrity of anuran sperm in fresh water for up to 6 hours showed an extremely high osmotic tolerance relative to fish sperm. The very high longevity and osmotic tolerance of anuran sperm and high longevity of cryptobranchid sperm, relative to those of freshwater fish, may reflect the complex fertilization history of amphibian sperm in

  12. Formation of inclusion complexes between high amylose starch and octadecyl ferulate via steam jet cooking

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Amylose can form inclusion complexes with guest molecules and represents an interesting approach to deliver bioactive molecules. However, ferulic acid has been shown not to form single helical inclusion complexes with amylose. To overcome this problem a ferulic acid ester, octadecyl ferulate, posses...

  13. A Silicate Inclusion in Puente del Zacate, a IIIA Iron Meteorite

    NASA Astrophysics Data System (ADS)

    Olsen, Edward J.; Davis, Andrew M.; Clayton, Robert N.; Mayeda, Toshiko K.; Moore, Carleton B.; Steele, Ian M.

    1996-09-01

    The IIIA and IIIB iron meteorites are considered to have formed in the cores of asteroids. A silicate inclusion within the IIIA meteorite Puente del Zacate consisting of olivine (Fa_4), low-calcium pyroxene (Fs_6Wo_1), chromium diopside (Fs_3Wo47), plagioclase (An14Or_4), graphite, troilite, chromite, daubreelite, and iron metal resembles inclusions in IAB iron meteorites. The oxygen isotopic composition of the Puente del Zacate inclusion is like chromite and phosphate inclusions in other IIIA and IIIB irons. The Puente del Zacate inclusion may have been derived from the lower mantle of the IIIAB parent asteroid.

  14. Innovation for an Inclusive Future

    NASA Astrophysics Data System (ADS)

    Springett, Mark; Rice, Mark; Carmichael, Alex; Griffiths, Richard

    This workshop will focus on setting the agenda for research, practice and policy in support of inclusive design for third generation computer-based products. The next generation of technology represents an unprecedented opportunity to improve the quality of life for groups of users who have previously faced exclusion, such as those with impairments and older citizens. At the same time it risks creating a greater digital divide and further exclusion. How we approach design for this new generation will determine whether or not the third wave will provide positive advances towards an inclusive digital world. We therefore need to put forward both a rationale for inclusive design and provide pointers towards technical development and design practice in support of inclusion. It is our belief that there is not only a strong moral case for design for inclusion but also significant commercial incentive, which may be key to persuading influential players to focus on inclusion. Therefore one of our key objectives is to describe and promote the advantages of designing ‘in from the edges’ of the user population rather than designing for a notional ‘average’ user.

  15. Fluid inclusion study of some Sarrabus fluorite deposits, Sardinia, Italy.

    USGS Publications Warehouse

    Belkin, H.E.; de Vivo, B.; Valera, R.

    1984-01-01

    Fluid inclusions in six deposits of fluorite fracture fillings associated with Hercynian (Carboniferous) cycle magmatism were studied by microthermometric techniques. All the inclusions were liquid dominated, aqueous, and homogenized in the liquid phase. One-phase (liquid), two-phase (liquid + vapour) and three-phase (liquid, vapour, and solid NaCl daughter mineral) fluid inclusions were noted. This study indicates that five of the fluorite deposits formed from 95o-125oC fluids with approx 15 wt.% NaCl. One other deposit appears to have been formed by very dilute solutions at approx 125oC. It is suggested that the local fluorite-forming process was the formation of fracture-localized hydrothermal systems in which magmatic water interaction with some other fluid-connate, meteoric, or marine.-G.J.N.

  16. Purification of recombinant ovalbumin from inclusion bodies of Escherichia coli.

    PubMed

    Upadhyay, Vaibhav; Singh, Anupam; Panda, Amulya K

    2016-01-01

    Recombinant ovalbumin expressed in bacterial host is essentially free from post-translational modifications and can be useful in understanding the structure-function relationship of the protein. In this study, ovalbumin was expressed in Escherichia coli in the form of inclusion bodies. Ovalbumin inclusion bodies were solubilized using urea and refolded by decreasing the urea concentration by dilution. Refolded protein was purified by anion exchange chromatography. Overall recovery of purified recombinant ovalbumin from inclusion bodies was about 30% with 98% purity. Purified recombinant ovalbumin was characterized by mass spectrometry, circular dichroism and fluorescence spectroscopy. Recombinant ovalbumin was shown to be resistant to trypsin using protease resistance assay. This indicated proper refolding of ovalbumin from inclusion bodies of E. coli. This method provides a simple way of producing ovalbumin free of post-translational modifications.

  17. Dynamic inclusion complexes of metal nanoparticles inside nanocups.

    PubMed

    Alarcón-Correa, Mariana; Lee, Tung-Chun; Fischer, Peer

    2015-06-01

    Host-guest inclusion complexes are abundant in molecular systems and of fundamental importance in living organisms. Realizing a colloidal analogue of a molecular dynamic inclusion complex is challenging because inorganic nanoparticles (NPs) with a well-defined cavity and portal are difficult to synthesize in high yield and with good structural fidelity. Herein, a generic strategy towards the fabrication of dynamic 1:1 inclusion complexes of metal nanoparticles inside oxide nanocups with high yield (>70%) and regiospecificity (>90%) by means of a reactive double Janus nanoparticle intermediate is reported. Experimental evidence confirms that the inclusion complexes are formed by a kinetically controlled mechanism involving a delicate interplay between bipolar galvanic corrosion and alloying-dealloying oxidation. Release of the NP guest from the nanocups can be efficiently triggered by an external stimulus.

  18. CAP1 was associated with actin and involved in Schwann cell differentiation and motility after sciatic nerve injury.

    PubMed

    Zhu, Xinhui; Yao, Li; Guo, Aisong; Li, Aihong; Sun, Huiqing; Wang, Ning; Liu, Hanzhang; Duan, Zhiqin; Cao, Jianhua

    2014-06-01

    Adenylate cyclase-associated protein 1 (CAP1), a member of cyclase-associated proteins that regulating actin dynamics, was shown to regulate actin filaments, localize to dynamic actin structures and mediate such processes as establishment of cell polarity, motility, morphogenesis, receptor-mediated endocytosis and mRNA location. But little is known about the role of CAP1 during peripheral nervous system injury. Here, we found the spatiotemporal protein expression of CAP1 after sciatic nerve crush. After crush, CAP1 had an increased protein expression level, reached a peak at about day 5 and then returned to the normal level at 4 weeks, similar to Oct-6. Besides, in 5-day injured tissue, using double immunofluorescent staining we found CAP1 had a colocalization with S100 and Oct-6. In vitro, during the process of cAMP-induced Schwann cells differentiation, we observed enhanced expression of CAP1 and P0. Specially, CAP1-specific siRNA-tranfected SCs did not show significant actin structure which form cellure surface tension and protrusion shape after cAMP treatment. And we observed the interaction of CAP1 with actin and that CAP1-specific siRNA-transfected SCs had a decreased motility and migration. Together, all these data indicated that the change of CAP1 protein expression was associated with Schwann cells motility and differentiation after the crush of sciatic nerve.

  19. The Sinorhizobium meliloti ntrX gene is involved in succinoglycan production, motility, and symbiotic nodulation on alfalfa.

    PubMed

    Wang, Dong; Xue, Haiying; Wang, Yiwen; Yin, Ruochun; Xie, Fang; Luo, Li

    2013-12-01

    Rhizobia establish a symbiotic relationship with their host legumes to induce the formation of nitrogen-fixing nodules. This process is regulated by many rhizobium regulators, including some two-component regulatory systems (TCSs). NtrY/NtrX, a TCS that was first identified in Azorhizobium caulinodans, is required for free-living nitrogen metabolism and symbiotic nodulation on Sesbania rostrata. However, its functions in a typical rhizobium such as Sinorhizobium meliloti remain unclear. Here we found that the S. meliloti response regulator NtrX but not the histidine kinase NtrY is involved in the regulation of exopolysaccharide production, motility, and symbiosis with alfalfa. A plasmid insertion mutant of ntrX formed mucous colonies, which overproduced succinoglycan, an exopolysaccharide, by upregulating its biosynthesis genes. This mutant also exhibited motility defects due to reduced flagella and decreased expression of flagellins and regulatory genes. The regulation is independent of the known regulatory systems of ExoR/ExoS/ChvI, EmmABC, and ExpR. Alfalfa plants inoculated with the ntrX mutant were small and displayed symptoms of nitrogen starvation. Interestingly, the deletion mutant of ntrY showed a phenotype similar to that of the parent strain. These findings demonstrate that the S. meliloti NtrX is a new regulator of succinoglycan production and motility that is not genetically coupled with NtrY.

  20. [On the significance of Solcoseryl on fertility. 1. The effect of Solcoseryl on sperm motility in vitro].

    PubMed

    Mattheus, A; Heise, H; Hofmann, R

    1980-01-01

    The effect of different Solcoseryl (Solco, Basel, Switzerland) concentrations on the motility of human sperm were tested on 37 ejaculates taken from two subject groups. Altogether 111 motility studies were performed using the eosine vitality test. In view of the considerable variations associated with motility tests, Solcoseryl appeared to have no effect on sperm motility in the majority of cases in group 1. The observed improvement in motility (20%) was countered by still greater motility losses (27%). The results, obtained by studies on selected asthenospermia (group 2) are different, however: the 26% increase in motility was opposed to a motility loss of only 17%. A Solcoseryl concentration of 50% was found to have the best effects on motility. A general rise in sperm motility by means of Solcoseryl cannot be considered, although tests would appear advisable in isolated instances. Solcoseryl may be a valuable protective resuspension agent for insemination purposes.

  1. The eukaryotic signal sequence, YGRL, targets the chlamydial inclusion

    PubMed Central

    Kabeiseman, Emily J.; Cichos, Kyle H.; Moore, Elizabeth R.

    2014-01-01

    Understanding how host proteins are targeted to pathogen-specified organelles, like the chlamydial inclusion, is fundamentally important to understanding the biogenesis of these unique subcellular compartments and how they maintain autonomy within the cell. Syntaxin 6, which localizes to the chlamydial inclusion, contains an YGRL signal sequence. The YGRL functions to return syntaxin 6 to the trans-Golgi from the plasma membrane, and deletion of the YGRL signal sequence from syntaxin 6 also prevents the protein from localizing to the chlamydial inclusion. YGRL is one of three YXXL (YGRL, YQRL, and YKGL) signal sequences which target proteins to the trans-Golgi. We designed various constructs of eukaryotic proteins to test the specificity and propensity of YXXL sequences to target the inclusion. The YGRL signal sequence redirects proteins (e.g., Tgn38, furin, syntaxin 4) that normally do not localize to the chlamydial inclusion. Further, the requirement of the YGRL signal sequence for syntaxin 6 localization to inclusions formed by different species of Chlamydia is conserved. These data indicate that there is an inherent property of the chlamydial inclusion, which allows it to recognize the YGRL signal sequence. To examine whether this “inherent property” was protein or lipid in nature, we asked if deletion of the YGRL signal sequence from syntaxin 6 altered the ability of the protein to interact with proteins or lipids. Deletion or alteration of the YGRL from syntaxin 6 does not appreciably impact syntaxin 6-protein interactions, but does decrease syntaxin 6-lipid interactions. Intriguingly, data also demonstrate that YKGL or YQRL can successfully substitute for YGRL in localization of syntaxin 6 to the chlamydial inclusion. Importantly and for the first time, we are establishing that a eukaryotic signal sequence targets the chlamydial inclusion. PMID:25309881

  2. Factors Affecting the Inclusion Potency for Acicular Ferrite Nucleation in High-Strength Steel Welds

    NASA Astrophysics Data System (ADS)

    Kang, Yongjoon; Jeong, Seonghoon; Kang, Joo-Hee; Lee, Changhee

    2016-06-01

    Factors affecting the inclusion potency for acicular ferrite nucleation in high-strength weld metals were investigated and the contribution of each factor was qualitatively evaluated. Two kinds of weld metals with different hardenabilities were prepared, in both, MnTi2O4-rich spinel formed as the predominant inclusion phase. To evaluate the factors determining the inclusion potency, the inclusion characteristics of size, phase distribution in the multiphase inclusion, orientation relationship with ferrite, and Mn distribution near the inclusion were analyzed. Three factors affecting the ferrite nucleation potency of inclusions were evaluated: the Baker-Nutting (B-N) orientation relationship between ferrite and the inclusion; the formation of an Mn-depleted zone (MDZ) near the inclusion; and the strain energy around the inclusion. Among these, the first two factors were found to be the most important. In addition, it was concluded that the increased chemical driving force brought about by the formation of an MDZ contributed more to the formation of acicular ferrite in higher-strength weld metals, because the B-N orientation relationship between ferrite and the inclusion was less likely to form as the transformation temperature decreased.

  3. Effects of environment factors on initiation of sperm motility in sea cucumber Apostichopus japonicus (Selenka)

    NASA Astrophysics Data System (ADS)

    Yu, Li; Shao, Mingyu; Bao, Zhenmin; Hu, Jingjie; Zhang, Zhifeng

    2011-06-01

    Sperm of sea cucumber Apostichopus japonicus (Selenka) were quiescent in electrolyte NaCl solution and artificial seawater (ASW) and nonelectrolyte glucose and mannitol solutions when the osmolality was less than 200 mOsm kg-1. The sperm started to be motile as a result of increased osmolality, indicating an osmolality-dependent initiation of sperm motility in sea cucumber. After a brief incubation in hypotonic NaCl and glucose solutions with osmolalities of 200 and 400 mOsm kg-1, sperm lost partial motile ability. Sperm became immobilized when pH was 6.0 in NaCl, glucose and mannitol solutions, suggesting that an H+ release is involved in sperm activation. The decreased pH had no effect on the percentage of motile sperm in ASW, whereas it delayed the time period to reach the maximum motility (motilitymax). Extracellular Ca2+ in electrolyte solutions was not essential for motility stimulation but shortened the time of reaching motilitymax. When Ca2+ was mixed in nonelectrolyte solutions the sperm motility was completely suppressed. The K+ channel blocker, quinine, suppressed the sperm motility in electrolyte solution, showing a possible involvement of K+ transport in the process. High K+ concentration did not affect the sperm motility in NaCl solution, but decreased it in ASW and almost entirely suppressed it in nonelectrolyte solutions. The different effects of pH and K+ in ASW and NaCl solution indicate that external ions may also regulate sperm motility.

  4. The role of calcium and Ca2+-ATPase in maintaining motility in ram spermatozoa.

    PubMed

    Breitbart, H; Rubinstein, S; Nass-Arden, L

    1985-09-25

    Extracellular calcium at millimolar concentrations inhibits collective motility of ejaculated ram spermatozoa. In untreated cells, or when motility was made dependent upon glycolytic activity, there is very small inhibition, but when motility was made dependent upon mitochondrial respiration there is very high inhibition in motility by increasing extracellular Ca2+ concentration. Quercetin, which inhibits (Ca2+ + Mg2+)-ATPase activity in isolated plasma membranes, also inhibits motility mainly in cells that have been made dependent upon glycolytic activity, but there is also inhibition in untreated cells. When motility was made dependent upon mitochondrial activity, there is no inhibition but rather some stimulation in motility by quercetin. The inhibitory effect of quercetin is enhanced by increasing Ca2+ concentration in the medium. Quercetin also inhibits uptake of calcium into the cells, in a mechanism by which a calcium channel is involved. This inhibition is high only when the glycolysis is inhibited in the cells. The rate of glycolysis is decreased by quercetin or ouabain, but their effects on motility are quite different. Based on these data, it appears that the plasma membrane (Ca2+ + Mg2+)-ATPase or the Ca2+ pump have a functional role in the regulation of spermatozoa motility. This motility regulation is functioning through mechanisms which include glycolytic activity and maintenance of intracellular calcium concentrations.

  5. Cranberry derivatives enhance biofilm formation and transiently impair swarming motility of the uropathogen Proteus mirabilis HI4320.

    PubMed

    O'May, Che; Amzallag, Olivier; Bechir, Karim; Tufenkji, Nathalie

    2016-06-01

    Proteus mirabilis is a major cause of catheter-associated urinary tract infection (CAUTI), emphasizing that novel strategies for targeting this bacterium are needed. Potential targets are P. mirabilis surface-associated swarming motility and the propensity of these bacteria to form biofilms that may lead to catheter blockage. We previously showed that the addition of cranberry powder (CP) to lysogeny broth (LB) medium resulted in impaired P. mirabilis swarming motility over short time periods (up to 16 h). Herein, we significantly expanded on those findings by exploring (i) the effects of cranberry derivatives on biofilm formation of P. mirabilis, (ii) whether swarming inhibition occurred transiently or over longer periods more relevant to real infections (∼3 days), (iii) whether swarming was also blocked by commercially available cranberry juices, (iv) whether CP or cranberry juices exhibited effects under natural urine conditions, and (v) the effects of cranberry on medium pH, which is an indirect indicator of urease activity. At short time scales (24 h), CP and commercially available pure cranberry juice impaired swarming motility and repelled actively swarming bacteria in LB medium. Over longer time periods more representative of infections (∼3 days), the capacity of the cranberry material to impair swarming diminished and bacteria would start to migrate across the surface, albeit by exhibiting a different motility phenotype to the regular "bull's-eye" swarming phenotype of P. mirabilis. This bacterium did not swarm on urine agar or LB agar supplemented with urea, suggesting that any potential application of anti-swarming compounds may be better suited to settings external to the urine environment. Anti-swarming effects were confounded by the ability of cranberry products to enhance biofilm formation in both LB and urine conditions. These findings provide key insights into the long-term strategy of targeting P. mirabilis CAUTIs.

  6. Phosphoinositide 3-kinase signaling is critical for ErbB3-driven breast cancer cell motility and metastasis

    PubMed Central

    Smirnova, Tatiana; Zhou, Zhen Ni; Flinn, Rory J.; Wyckoff, Jeffrey; Boimel, Pamela J.; Pozzuto, Maria; Coniglio, Salvatore J.; Backer, Jonathan M.; Bresnick, Anne R.; Condeelis, John S.; Hynes, Nancy E.; Segall, Jeffrey E.

    2011-01-01

    Many malignancies show increased expression of the EGF receptor family member ErbB3 (HER3). ErbB3 binds beta-1 (HRGβ1), and forms a heterodimer with other ErbB family members, such as ErbB2 (HER2) or EGFR (HER1), enhancing phosphorylation of specific C terminal tyrosine residues and activation of downstream signaling pathways. ErbB3 contains six YXXM motifs that bind the p85 subunit of PI3-kinase. Previous studies demonstrated that overexpression of ErbB3 in mammary tumor cells can significantly enhance chemotaxis to HRGβ1 and overall metastatic potential. We tested the hypothesis that ErbB3-mediated PI3-kinase signaling is critical for heregulin-induced motility, and therefore crucial for ErbB3-mediated invasion, intravasation and metastasis. The tyrosines in the six YXXM motifs on the ErbB3 C-terminus were replaced with phenylalanine. In contrast to overexpression of the wild-type ErbB3, overexpression of the mutant ErbB3 did not enhance chemotaxis towards HRGβ1 in vitro or in vivo. We also observed reduced tumor cell motility in the primary tumor by multiphoton microscopy, as well as a dramatically reduced ability of these cells to cross the endothelium and intravasate into the circulation. Moreover, while mutation of the ErbB3 C-terminus had no effect on tumor growth, it had a dramatic effect on spontaneous metastatic potential. Treatment with the PI3-kinase inhibitor PIK-75 similarly inhibited motility and invasion in vitro and in vivo. Our results indicate that stimulation of the early metastatic steps of motility and invasion by ErbB3 requires activation of the PI3-kinase pathway by the ErbB3 receptor. PMID:21725367

  7. Nucleocapsid of Tomato spotted wilt tospovirus forms mobile particles that traffic on an actin/endoplasmic reticulum network driven by myosin XI-K.

    PubMed

    Feng, Zhike; Chen, Xiaojiao; Bao, Yiqun; Dong, Jiahong; Zhang, Zhongkai; Tao, Xiaorong

    2013-12-01

    A number of viral proteins from plant viruses, other than movement proteins, have been shown to traffic intracellularly along actin filaments and to be involved in viral infection. However, there has been no report that a viral capsid protein may traffic within a cell by utilizing the actin/endoplasmic reticulum (ER) network. We used Tomato spotted wilt tospovirus (TSWV) as a model virus to study the cell biological properties of a nucleocapsid (N) protein. We found that TSWV N protein was capable of forming highly motile cytoplasmic inclusions that moved along the ER and actin network. The disruption of actin filaments by latrunculin B, an actin-depolymerizing agent, almost stopped the intracellular movement of N inclusions, whereas treatment with a microtubule-depolymerizing reagent, oryzalin, did not. The over-expression of a myosin XI-K tail, functioning in a dominant-negative manner, completely halted the movement of N inclusions. Latrunculin B treatment strongly inhibited the formation of TSWV local lesions in Nicotiana tabacum cv Samsun NN and delayed systemic infection in N. benthamiana. Collectively, our findings provide the first evidence that the capsid protein of a plant virus has the novel property of intracellular trafficking. The findings add capsid protein as a new class of viral protein that traffics on the actin/ER system.

  8. Adenosine triphosphate acts as a paracrine signaling molecule to reduce the motility of T cells.

    PubMed

    Wang, Chiuhui Mary; Ploia, Cristina; Anselmi, Fabio; Sarukhan, Adelaida; Viola, Antonella

    2014-06-17

    Organization of immune responses requires exchange of information between cells. This is achieved through either direct cell-cell contacts and establishment of temporary synapses or the release of soluble factors, such as cytokines and chemokines. Here we show a novel form of cell-to-cell communication based on adenosine triphosphate (ATP). ATP released by stimulated T cells induces P2X4/P2X7-mediated calcium waves in the neighboring lymphocytes. Our data obtained in lymph node slices suggest that, during T-cell priming, ATP acts as a paracrine messenger to reduce the motility of lymphocytes and that this may be relevant to allow optimal tissue scanning by T cells.

  9. Growth, collapse, and stalling in a mechanical model for neurite motility

    NASA Astrophysics Data System (ADS)

    Recho, Pierre; Jerusalem, Antoine; Goriely, Alain

    2016-03-01

    Neurites, the long cellular protrusions that form the routes of the neuronal network, are capable of actively extending during early morphogenesis or regenerating after trauma. To perform this task, they rely on their cytoskeleton for mechanical support. In this paper, we present a three-component active gel model that describes neurites in the three robust mechanical states observed experimentally: collapsed, static, and motile. These states arise from an interplay between the physical forces driven by growth of the microtubule-rich inner core of the neurite and the acto-myosin contractility of its surrounding cortical membrane. In particular, static states appear as a mechanical traction or compression balance of these two parallel structures. The model predicts how the response of a neurite to a towing force depends on the force magnitude and recovers the response of neurites to several drug treatments that modulate the cytoskeleton active and passive properties.

  10. Effects of Lizhong Tang on gastrointestinal motility in mice

    PubMed Central

    Lee, Min Cheol; Ha, Wooram; Park, Jinhyeong; Kim, Junghoon; Jung, Yunjin; Kim, Byung Joo

    2016-01-01

    AIM To investigate the effects of Lizhong Tang, a traditional Chinese medicine formula, on gastrointestinal motility in mice. METHODS The in vivo effects of Lizhong Tang on GI motility were investigated by measuring the intestinal transit rates (ITRs) and gastric emptying (GE) values in normal mice and in mice with experimentally induced GI motility dysfunction (GMD). RESULTS In normal ICR mice, the ITR and GE values were significantly and dose-dependently increased by Lizhong Tang (ITR values: 54.4% ± 1.9% vs 65.2% ± 1.8%, P < 0.01 with 0.1 g/kg Lizhong Tang and 54.4% ± 1.9% vs 83.8% ± 1.9%, P < 0.01 with 1 g/kg Lizhong Tang; GE values: 60.7% ± 1.9% vs 66.8% ± 2.1%, P < 0.05 with 0.1 g/kg Lizhong Tang and 60.7% ± 1.9% vs 72.5% ± 1.7%, P < 0.01 with 1 g/kg Lizhong Tang). The ITRs of the GMD mice were significantly reduced compared with those of the normal mice, which were significantly and dose-dependently reversed by Lizhong Tang. Additionally, in loperamide- and cisplatin-induced models of GE delay, Lizhong Tang administration reversed the GE deficits. CONCLUSION These results suggest that Lizhong Tang may be a novel candidate for development as a prokinetic treatment for the GI tract. PMID:27678361

  11. Multiple-exposure photographic analysis of a motile spirochete.

    PubMed Central

    Goldstein, S F; Charon, N W

    1990-01-01

    The Leptospiraceae are thin spirochetes with a unique mode of motility. These spiral-shaped bacteria have internal periplasmic flagella that propel the cells in low-viscosity and gel-like high-viscosity media. A model of Leptospiraceae motility has been previously proposed that states that the subterminally attached periplasmic flagella rotate between the outer sheath and the helical protoplasmic cylinder. The shape of the cell ends and the direction of gyration of these ends are determined by the direction of rotation of the internal periplasmic flagella. Rotation of the periplasmic flagella in one direction causes that end to be spiral-shaped, and rotation in the other direction causes that end to be hook-shaped. One prediction of the model is that these right-handed spirochetes roll clockwise when swimming away from an observer. For maximum swimming efficiency, the model predicts that the sense of the spiral-shaped end is left-handed and gyrates counterclockwise. The present study presents direct evidence that the cell rolls clockwise (protoplasmic cylinder helix diameter = 0.24 micron; pitch = 0.69 micron), the ends gyrate counterclockwise, and the spiral-shaped end is left-handed (helix diameter = 0.6 micron; pitch = 2.7 microns)--as predicted by the model. The hook-shaped end appears approximately planar. The approach used was to illuminate stroboscopically cells slowed by Ficoll and analyze the resultant multiple-exposure photographs focused above and below the axis of the cell. The methodology used should be helpful in analyzing the motility of the larger and more complex spirochetes. Images PMID:2367518

  12. Evaluation of antral motility in humans using manometry and scintigraphy.

    PubMed Central

    Jones, K; Edelbroek, M; Horowitz, M; Sun, W M; Dent, J; Roelofs, J; Muecke, T; Akkermans, L

    1995-01-01

    Recent studies suggest that scintigraphy can be used to evaluate non-invasively antral motility in humans, although scintigraphic techniques have not yet been compared with more conventional measurements of intraluminal pressures by manometry. Simultaneous scintigraphic and manometric measurements of antral motility were performed in nine healthy volunteers. After intubation with a sleeve/sidehole catheter which incorporated five pressure sideholes located at 1.5 cm intervals spanning the antrum, each subject ingested 100 g minced beef labelled with 100 MBq 99mTc-chicken liver and 150 ml water. Between 40-43, 60-63, 80-83, and 100-103 minutes after meal ingestion, radioisotopic data were acquired in two second frames. Time-activity curves showing antral 'contractions' resulting from wall motion were derived by drawing small regions of interest over the antrum to coincide with the position of the antral manometric sideholes. Scintigraphic contraction rates approximated 3/minute, whereas antral pressure waves that occluded the lumen were less frequent (p < 0.01 for all), particularly in the proximal antrum. The amplitude of wall motion, evaluated scintigraphically, and the amplitude of pressure waves were both inversely related to the distance from the pylorus (r > -0.32, p < 0.05) and antral volume r > -0.29 (p < 0.05). There were significant relationships between the amplitude of contractions assessed scintigraphically and the number of lumen-occlusive antral pressure waves in the distal antrum (r -0.48, p < 0.05) but not in the more proximal antral regions. It is concluded that scintigraphy can detect antral wall motion with greater sensitivity than manometry, particularly in the proximal antrum. As manometry gives information on the amplitude as well as the temporal and spatial organisation of those contractions which result in lumen occlusion, the combination of scintigraphic and manometric techniques in the evaluation of antral motility shows considerable

  13. Altered motility causes the early gastrointestinal toxicity of irradiation

    SciTech Connect

    Erickson, B.A.; Moulder, J.E.; Otterson, M.F.; Sarna, S.K. )

    1994-03-01

    This article reviews studies of large and small intestinal contractile activity following radiation exposure. Studies of motility utilize strain gauge transducers surgically implanted on the seromuscular layer of the small intestine. All studies were performed in mixed breed dogs to record the occurrence of normal contractions, giant migrating contractions (GMCs) and retrograde giant contractions (RGCs) before, during and after irradiation (22.5 Gy in 9 fractions at 3 fractions/week). Giant migrating contractions and retrograde giant contractions are infrequent in the healthy state. However, in diseased states, GMCs are associated with abdominal cramps and diarrhea, and RGCs precede vomiting. In fasted animals, fractionated abdominal irradiation dramatically increased the frequency of GMCs, with the incidence peaking after the second dose. The increased frequency of GMCS occurred as early as a few hours after the first radiation fraction, and returned to normal within days of cessation of radiation. RGCs were also significantly increased after abdominal irradiation. The frequency of RGCs was greatest on the first and sixth dose of radiation. Clinically, the dogs developed nausea, vomiting and diarrhea as early as the first day of irradiation. In dogs studied in the fed state, decreased amplitude, duration, and frequency of postprandial contractions occurred. These changes may slow intestinal transit during irradiation. Radiation also produced a striking increase in the frequency of colonic GMCs; these changes in colonic motor activity were associated with diarrhea as early as the second irradiation. Changes in GI motility during fractionated irradiation precede the appearance of histopathological lesions in the GI tract. Thus, the symptoms of nausea, vomiting, and diarrhea experienced during radiotherapy (particularly those within the first week) are directly related to changes in bowel motility. 41 refs., 7 figs., 1 tab.

  14. Viscumins functionally modulate cell motility-associated gene expression.

    PubMed

    Schötterl, Sonja; Hübner, Miriam; Armento, Angela; Veninga, Vivien; Wirsik, Naita Maren; Bernatz, Simon; Lentzen, Hans; Mittelbronn, Michel; Naumann, Ulrike

    2017-02-01

    In Europe extracts from Viscum album L., the European white-berry mistletoe, are widely used as a complementary cancer therapy. Viscumins (mistletoe lectins, ML) have been scrutinized as important active components of mistletoe and exhibit a variety of anticancer effects such as stimulation of the immune system, induction of cytotoxicity, reduction of tumor cell motility as well as changes in the expression of genes associated with cancer development and progression. By microarray expression analysis, quantitative RT-PCR and RT-PCR based validation of microarray data we demonstrate for the Viscum album extract Iscador Qu and for the lectins Aviscumine and ML-1 that in glioma cells these drugs differentially modulate the expression of genes involved in the regulation of cell migration and invasion, including processes modulating cell architecture and cell adhesion. A variety of differentially expressed genes in ML treated cells are associated with the transforming growth factor (TGF)-β signaling pathway or are targets of TGF-β. ML treatment downregulated the expression of TGF-β itself, of the TGF-β receptor II (TGFBR2), of the TGF-β intracellular signal transducer protein SMAD2, and of matrix-metalloproteinases (MMP) MMP-2 and MMP-14. Even if the changes in gene expression differ between Aviscumine, Iscador Qu and ML-1, the overall regulation of motility associated gene expression by all drugs showed functional effects since tumor cell motility was reduced in a ML-dependent manner. Therefore, ML containing compounds might provide clinical benefit as adjuvant therapeutics in the treatment of patients with invasively growing tumors such as glioblastomas.

  15. Diverse Perspectives on Inclusive School Communities

    ERIC Educational Resources Information Center

    Tsokova, Diana; Tarr, Jane

    2012-01-01

    What is an inclusive school community? How do stakeholders perceive their roles and responsibilities towards inclusive school communities? How can school communities become more inclusive through engagement with individual perspectives? "Diverse Perspectives on Inclusive School Communities" captures and presents the voices of a wide…

  16. Exploring Preservice Teachers' Attitudes Towards Inclusion

    ERIC Educational Resources Information Center

    Killoran, Isabel; Woronko, Dagmara; Zaretsky, Hayley

    2014-01-01

    This study responds to a call for research into existing teacher-education programmes and their impact on teacher candidates' attitudes. An inclusive education course that examined the difference between "soft inclusion" (inclusion which addresses the issue of place rather than substance of learning) and genuine inclusion was used to…

  17. Inclusion 101: How To Teach All Learners.

    ERIC Educational Resources Information Center

    Bauer, Anne M.; Shea, Thomas M.

    This book is designed to help educators provide effective instruction to students with disabilities in inclusive classrooms. Chapters address: (1) the concepts of inclusive society, schools, classrooms and services; (2) legal foundations for inclusion and government support for education; (3) the qualities of inclusive schools and classrooms; (4)…

  18. Gastrointestinal Motility, Part 2: Small-Bowel and Colon Transit.

    PubMed

    Maurer, Alan H

    2016-03-01

    Because of the difficulty often encountered in deciding whether a patient's symptoms originate in the upper or lower gastrointestinal tract, gastrointestinal transit scintigraphy is a uniquely suited noninvasive, quantitative, and physiologic method of determining whether there is a motility disorder affecting the stomach, small bowel, or colon. Small-bowel and colon transit studies can be performed alone or together with gastric emptying studies after oral administration of an appropriately radiolabeled meal. It is hoped that newly published standards for performing these studies and the anticipated arrival of new Current Procedural Terminology codes in the United States for small-bowel and colon transit studies will increase their availability and use.

  19. Gastrointestinal Motility, Part 2: Small-Bowel and Colon Transit.

    PubMed

    Maurer, Alan H

    2015-09-01

    Because of the difficulty often encountered in deciding whether a patient's symptoms originate in the upper or lower gastrointestinal tract, gastrointestinal transit scintigraphy is a uniquely suited noninvasive, quantitative, and physiologic method of determining whether there is a motility disorder affecting the stomach, small bowel, or colon. Small-bowel and colon transit studies can be performed alone or together with gastric emptying studies after oral administration of an appropriately radiolabeled meal. It is hoped that newly published standards for performing these studies and the anticipated arrival of new Current Procedural Terminology codes in the United States for small-bowel and colon transit studies will increase their availability and use.

  20. Cancer cell motility: lessons from migration in confined spaces

    PubMed Central

    Paul, Colin D.; Mistriotis, Panagiotis; Konstantopoulos, Konstantinos

    2017-01-01

    Time-lapse, deep-tissue imaging made possible by advances in intravital microscopy has demonstrated the importance of tumour cell migration through confining tracks in vivo. These tracks may either be endogenous features of tissues or be created by tumour or tumour-associated cells. Importantly, migration mechanisms through confining microenvironments are not predicted by 2D migration assays. Engineered in vitro models have been used to delineate the mechanisms of cell motility through confining spaces encountered in vivo. Understanding cancer cell locomotion through physiologically relevant confining tracks could be useful in developing therapeutic strategies to combat metastasis. PMID:27909339